Winter Trees and Shrubs: Northern Catalpa

The names of plants often contain clues that can either help with identification or that tell something about the plant’s history or use. The name, catalpa, is said to be derived from the Muscogee word, katałpa, meaning “winged head,” presumably referring to the tree’s winged seeds. Or maybe, as one writer speculates, it refers to the large, heart-shaped, floppy leaves that can make it look like the tree is “ready to take flight.” Or perhaps it’s a reference to the fluted, fused petals of the tree’s large, tubular flowers. I suppose it could mean any number of things, but I’m sticking with its seeds, which are packed by the dozens in the tree’s long, slender, bean-like fruits. The seeds are flat, pale brown, and equipped with paper thin, fringed appendages on either side that assist in wind dispersal – wings, in other words.

winged seeds of northern catalpa (Catalpa speciosa)

Catalpa speciosa, or northern catalpa, is a relatively fast growing, short-lived tree native to the Midwest and one of only two species in the genus Catalpa found in the United States. Its distribution prior to the arrival of Europeans appears to have been restricted to a portion of the central Mississippi River valley, extending west into Arkansas, east into Tennessee, and north into Illinois and Indiana. It has since been widely planted outside of its native range, naturalizing in areas across the Midwest and eastern US. Early colonizers planted northern catalpa for use as fence posts, railroad ties, and firewood. Its popularity as an ornamental tree is not what it once was a century ago, but it is still occasionally planted in urban areas as a shade tree. Its messiness – littering the ground below with large leaves, flowers, and seed capsules – and its tendency to spread outside of cultivation into natural areas are reasons why it has fallen out of favor with some people.

The oval to heart-shaped, 8 to 12 inch long leaves with long petioles rotting on the ground below the tree are one sure sign that you’ve encountered a catalpa in the winter time. The leaves are some of the first to fall at the end of the growing season, briefly turning an unmemorable yellow before dropping.

leaf of northern catalpa (Catalpa speciosa) in the winter with soft hairs on the underside still visible

The leaf arrangement on northern catalpa is whorled and sometimes opposite. The twigs are easy to identify due to several unique features. They are stout, round, and grayish brown with prominent lenticels. The leaf scars are large, rounded, and raised up on the twig, looking a bit like little suction cups. They are arranged in whorls of three, with one scar considerably smaller than the other two. A series of bundle traces inside the scar form an ellipse. The leaf buds are tiny compared to the scar and are protected by loose, pointed, brown bud scales. Northern catalpa twigs lack a terminal bud. In the winter, seed capsules or the stalk of an old inflorescence often remain attached to the terminal end of the twig. The pith inside of the twig is thick, white, and solid.

twig of northern catalpa (Catalpa speciosa)

pith inside twig of northern catalpa (Catalpa speciosa)

Another common name for Catalpa speciosa is cigar tree, a name that comes from its up to 18 inch long, cigar-like seed capsules that hang from the otherwise naked tree throughout the winter. The sturdy, cylindrical pod starts out green in the summer and turns dark brown by late fall. Seed pods that haven’t fallen or already split open will dehisce in the spring time, releasing their papery seeds to the wind.

fruits of northern catalpa (Catalpa speciosa) hanging from the tree in the winter

The young bark of northern catalpa is thin and easily damaged. As it matures, it becomes furrowed with either scaly ridges or blocky plates. Mature trees are generally twisted at the base but otherwise grow straight, reaching 30 to 60 feet tall (sometimes taller) with an open-rounded to narrow-oval crown.

maturing bark of northern catalpa (Catalpa speciosa)

Northern catalpa is one of the last trees to leaf out in the spring. In late spring or early summer, 10 inch long clusters of white, tubular flowers are produced at the tips of stems. Before the flowers open, they look a bit like popped popcorn, reminding me of a song from my childhood (which I will reluctantly leave right here). The margins of its trumpet-shaped petals are ruffled and there is yellow, orange, and/or purple spotting or streaking on the inside of the tubes.

flower of northern catalpa (Catalpa speciosa) just before it opens

More Winter Trees and Shrubs on Awkward Botany:

Winter Trees and Shrubs: Netleaf Hackberry

Boise, Idaho is frequently referred to as the City of Trees despite being located in a semiarid region of the Intermountain West known as the sagebrush steppe where few trees naturally grow. It earns this moniker partly because the name Boise is derived from the river that runs through it (the Boise River), which was named La Rivere Boisse, or The Wooded River, by early French trappers. Although it flows through a largely treeless landscape, The Wooded River was an apt name on account of the wide expanse of cottonwoods and willows that grew along its banks. The fervent efforts of early colonizers to plant trees in large numbers across their new city also helped Boise earn the title, City of Trees. Today, residents continue the legacy of planting trees, ensuring that the city will remain wooded for decades to come.

As is likely the case for most urban areas, the majority of trees being planted in Boise are not native to the region. After all, very few tree species are. However, apart from the trees that flank the Boise River, there is one tree in particular that naturally occurs in the area. Celtis reticulata, commonly known as netleaf hackberry, can be found scattered across the Boise Foothills amongst shrubs, bunchgrasses, and wildflowers, taking advantage of deep pockets of moisture found in rocky outcrops and draws.

The western edge of netleaf hackberry’s range extends to the northwest of Boise into Washington, west into Oregon, and down into California. The majority of its range is found south of Idaho, across the Southwest and into northern Mexico, then east into the prairie regions of Kansas and Oklahoma. Previously placed in the elm family, it is now considered a member of the family Cannabaceae (along with hemp and hops). It’s a relatively small, broad tree (sometimes a shrub) with a semi-rounded crown. It grows slowly, is long-lived, and generally has a gnarled, hardened, twisted look to it. It’s a tough tree that has clearly been through a lot.

The leaves of Celtis reticulata are rough, leathery, and oval to lance shaped with serrate or entire leaf margins. Their undersides have a distinct net-like pattern that gives the tree its common name. A very small insect called a hackberry psyllid lays its eggs inside the leaf buds of netleaf hackberries in the spring. Its larvae develop inside the leaf, feeding on the sugars produced during photosynthesis, and causing nipple galls to form in the leaves. It’s not uncommon to see a netleaf hackberry with warty-looking galls on just about every leaf. Luckily, the tree doesn’t seem to be bothered by this.

fallen leaves of netleaf hackberry (Celtis reticulata) with nipple galls

The fruit of netleaf hackberry is a pea-sized drupe that hangs at the end of a pedicel that is 1/4 to 1/2 inch long. Its skin is red-orange to purple-brown, and its flesh is thin with a large seed in the center. The fruits, along with a few random leaves, persist on the tree throughout the winter and provide food for dozens of species of birds and a variety of mammals.

persistent fruit of netleaf hackberry (Celtis reticulata)

Celtis reticulata is alternately branched. Its twigs are slender, zig-zagging, and often curved back towards the trunk. They are reddish-brown with several pale lenticels and have sparse, fine, short hairs that are hard to see without a hand lens. The leaf scars are small, half-round, and raised up from the twig. They have three bundle scars that form a triangle. The buds are triangle-shaped with fuzzy bud scales that are slightly lighter in color than the twig. The twigs are topped with a subterminal bud, and the pith (the inner portion of the twig) is either chambered or diaphragmed and difficult to see clearly without a hand lens. 

twigs of netleaf hackberry (Celtis reticulata)

The young bark of netleaf hackberry is generally smooth and grey, developing shallow, orange-tinged furrows as it gets older. Mature bark is warty like its cousin, Celtis occidentals, and develops thick, grey, corky ridges. Due to its slow growth, the bark can be retained long enough that it becomes habitat for extensive lichen colonies.

bark of young netleaf hackberry (Celtis reticulata)

bark of mature netleaf hackberry (Celtis reticulata)

Netleaf hackberry is one of the last trees to leaf out in the spring, presumably preserving as much moisture as possible as it prepares to enter another scorching hot, bone-dry summer typical of the western states. Its flowers open around the same time and are miniscule and without petals. Their oversized mustache-shaped, fuzzy, white stigmas provide some entertainment for those of us who take the time to lean in for a closer look.

spring flowers of netleaf hackberry (Celtis reticulata)

More Winter Trees and Shrubs on Awkward Botany:

———————

Photos of netleaf hackberry taken at Idaho Botanical Garden in Boise, Idaho.

Winter Trees and Shrubs: Eastern Redbud

Botanizing doesn’t have to end when the leaves fall off the trees and the ground goes frozen. Plants may stop actively growing during this time, but they are still there. Some die back to the soil level and spend the entire winter underground, leaving behind brown, brittle shells of their former selves. Others, particularly those with woody stems, maintain their form (although many of them leafless) as they bide their time while daylength dips and rises again, bringing with it the promise of warmer weather. Plants that leave us with something to look at during the winter can still be identified. Without foliage or flowers to offer us clues, we rely instead on branches, bark, and buds to identify woody species. In some cases, such features may even be more helpful in determining a certain species than their flowers and foliage ever were. Either way, it’s a fun challenge and one worth accepting if you’re willing to brave the cold, hand lens and field guides in tow.

In this series of posts I’ll be looking closely at woody plants in winter, examining the twigs, buds, bark, and any other features I come across that can help us identify them. Species by species, I will learn the ropes of winter plant identification and then pass my findings along to you. We’ll begin with Cercis canadensis, an understory tree commonly known as eastern redbud.

Eastern redbud is distributed across central and eastern North America, south of southern Michigan and into central Mexico. It is also commonly grown as an ornamental tree outside of its native range, and a number of cultivars have been developed for this purpose. Mature trees reach up to 30 feet and have short trunks with wide, rounded crowns. Its leaves are entire, round or heart-shaped, and turn golden-yellow in the fall. Gathered below the tree in winter, the leaves maintain their shape and are a light orange-brown color.

fallen leaf of eastern redbud (Cercis canadensis)

Eastern redbud is alternately branched with slender, zig-zagging twigs that are dark reddish-brown scattered with several tiny, light-colored lenticels. Older sections of branches are more grey in color. Leaf scars (the marks left on twigs after leaves fall) are a rounded triangle shape and slightly raised with thin ridges along each side. The top edge of the leaf scar is fringed, which I found impossible to see without magnification. Leaf buds are egg-shaped and 2-3 mm in length with wine-red bud scales that are glabrous (smooth) with slightly white, ciliate margins. Descriptions say there are actually two buds – one stalked and one sessile. If the second bud is there, it’s miniscule and obscured by the leaf scar. I haven’t actually been able to see one. Twigs lack a terminal bud or have a tiny subterminal bud that points off to one side. The pith of the twigs is rounded and pale pink. Use sharp pruners or a razor blade to cut the twig in half lengthwise to see it.

twig and buds of eastern redbud (Cercis canadensis)

Bark is helpful in identifying woody plants any time of year, but is especially worth looking at during the winter when branches have gone bare. The bark of young eastern redbud is grey with orange, furrowed streaks running lengthwise along the trunk. In mature trees, the bark is gray, scaly, and peels to reveal reddish-brown below.

bark of young eastern redbud (Cercis canadensis)

bark of mature eastern redbud (Cercis canadensis)

Eastern redbud is in the bean family (Fabaceae) and its flowers and fruits are characteristic of plants in this family. Fruits can persist on the tree throughout the winter and are another way to identify the tree during the off-season. Seed pods are flat, dark red- or orange-brown, and up to 2.5 inches long with four to ten seeds inside. The seeds are flat, round, about 5 millimeters long, and ranging in color from orange-brown to black.

persistent fruits of eastern redbud (Cercis canadensis)

seeds of eastern redbud (Cercis canadensis)

Eastern redbud flowers in early spring before it has leafed out. Clusters of bright pink flowers form on old branches rather than new stems and twigs. Sometimes flowers even burst right out of the main trunk. This unique trait is called cauliflory.

cauliflory on eastern redbud (Cercis canadensis)

———————

Photos of eastern redbud taken at Idaho Botanical Garden in Boise, Idaho.

Winter Interest in the Lower Boise Foothills

The Boise Foothills, a hilly landscape largely dominated by shrubs and grasses, are a picturesque setting any time of the year. They are particularly beautiful in the spring when a wide array of spring flowering plants are in bloom, and then again in late summer and early fall when a smaller selection of plants flower. But even when there aren’t flowers to see, plants and other features in the Foothills continue to offer interest. Their beauty may be more subtle and not as immediately striking as certain flowers can be, but they catch the eye nonetheless. Appeal can be found in things like gnarled, dead sagebrush branches, lichen covered rocks, and fading seed heads. Because the lower Boise Foothills in particular have endured a long history of plant introductions, an abundance of weeds and invasive plants residing among the natives also provide interest.

This winter has been another mild one. I was hoping for more snow, less rain, and deeper freezes. Mild, wet conditions make exploring the Foothills difficult and ill-advised. Rather than frozen and/or snow covered, the trails are thick with mud. Walking on them in this state is too destructive. Avoiding trails and walking instead on trail side vegetation is even more destructive, and so Foothills hiking is put on hold until the ground freezes or the trails dry out. This means I haven’t gotten into the Foothills as much as I would like. Still, I managed to get a few photos of some of the interesting things the lower Boise Foothills have to offer during the winter. What follows is a selection of those photos.

snow melting on the fruit of an introduced rose (Rosa sp.)

fading seed heads of hoary tansyaster (Machaeranthera canescens)

samaras of box elder (Acer negundo)

snow on seed heads of yarrow (Achillea millefolium)

gall on introduced rose (Rosa sp.)

sunflower seed heads (Helianthus annuus)

sunflower seed head in the snow (Helianthus annuus)

snow falling in the lower Boise Foothills

fading seed heads of salsify (Tragopogon dubius)

lichen on dead box elder log

seed head of curlycup gumweed (Grindelia squarrosa)

lichen and moss on rock in the snow

fruits of poison ivy (Toxicodendron radicans)

See Also: Weeds and Wildflowers of the Boise Foothills (June 2015)

———————-

The first issue of our new zine, Dispersal Stories, is available now. It’s an ode to traveling plants. You can find it in our Etsy Shop

Weeds and Winter Interest

In climates where winter sucks the garden inside itself and into quiet dormancy, it is often dead stalks and seed heads that provide the most visual interest. They also become, in some respects, a reminder of a garden that once was and what will be again.” — Gayla Trail, Grow Curious

If, like me, it is during the growing season that you really thrive, winters can be brutal. Color has practically been stripped from the landscape. Death and slumber abound. Nights are long and days are cold. It’s a lengthy wait until spring returns. Yet, my love of plants does not rest. And so, I look for beauty in a frozen landscape.

In evergreens, it is obvious. They maintain their color year-round. Large bunchgrasses, shrubs and trees with interesting bark or branching habits, dried fruits and unique seed heads – all of these things are easy to spot and visually interesting.

Beyond that, there are things that we are not accustomed to finding beauty in. Such things require a keen eye, close observation, and the cultivation of greater understanding and appreciation. For most people, weeds fall into this category. What is there to love or find beautiful?

I am of the opinion that there is plenty there to intrigue us. From their spent flowers to their seed heads and dried-up leaves, they can be just as interesting as the plants we deem more desirable. The winter-long green of winter annuals alone is evidence enough. So, here is my attempt to redeem some of these plants by nominating them as candidates for winter interest.

common mallow (Malva neglecta)

field bindweed (Convolvulus arvensis)

common mullein (Verbascum thapsus)

common dandelion (Taraxacum officinale)

Russian thistle (Kali tragus, syn. Salsola tragus)

Russian thistle (Kali tragus, syn. Salsola tragus)

redstem filaree (Erodium cicutarium)

curly dock (Rumex crispus)

curly dock (Rumex crispus)

prickly lettuce (Lactuca serriola)

salsify (Tragopogon dubius)

wood avens (Geum urbanum)

yellow evening primrose (Oenothera biennis)

annual honesty, a.k.a. money plant (Lunaria annua)

white clover (Trifolium repens)

———————

A friendly reminder: Refrain from being overly ambitious with your fall cleanup and, instead, leave certain plants in place. This not only provides winter interest but can also be beneficial to the wild creatures we share space with.

 

Our Backyard Farm and Garden Show: Fall 2014

I had every intention of documenting this year’s garden more thoroughly, but as things tend to go, the days got busy and the year got away from me. Now here we are in mid-October, still waiting for the first frost but accepting its imminence, watching reluctantly as another growing season comes to a close. We took several pictures but few notes, so what follows is a series of photos and a few reflections on what transpired this past year in, what Flora likes to call, Our Backyard Farm and Garden Show.

Abundance

Abundance

I guess I should start at the beginning. Last year I was living in an apartment. I was growing things in two small flower beds and a few containers on my patio. That had been my story for about a decade – growing what I could on porches and patios and in flower beds of various apartments in a few different parts of the country. At one point I was living in an apartment with no space at all to grow anything, and so I attempted to start a garden in the backyard of an abandoned, neighboring house – geurilla gardening style – but that didn’t go so well. At another location I had a plot at a community garden. The three years I spent there were fun, but definitely not as nice as stepping outside my door and into my garden.

Earlier this year, I moved in with Flora. She was renting a house with a yard, so when I joined her, I also joined her yard. Flora is a gardener, too; she had spent her first year here growing things in the existing garden spaces but wanted to expand. So we did. We enlarged three beds considerably and built four raised beds and two compost bins. We also got permission to grow things in the neighbor’s raised beds. And that’s how our growing season started – coalescence and expansion.

Then summer happened. It came and went, actually. Most days were spent just trying to keep everything alive – moving sprinklers around, warding off slugs and other bugs, and staking things up. Abundance was apparent pretty much immediately. We started harvesting greens (lettuce, kale, collards, mustards) en masse. Shortly after that, cucumbers appeared in concert with beets, turnips, basil, ground cherries, eggplants, tomatoes, carrots, peppers, etc. Even now – anticipating that first frost – the harvest continues. We are uncertain whether or not we will remain here for another growing season; regardless, we are considering the ways in which we might expand in case we do. Despite the amount of work that has gone into our garden so far, we still want to do more. Apparently, our love of gardening knows no bounds.

A view of our side yard. It is pretty shady in this section of the yard but we were still able to grow kale and collards along with several different flowers and herbs.

A view of our side yard. It is pretty shady in this bed but we were still able to grow kale and collards along with several different flowers and herbs.

 

We grew several varieties of lettuce. This is one that I was most excited about. It's called 'Tennis Ball.' It is a miniature butterhead type that Thomas Jefferson loved and used to grow in his garden at Monticello.

We grew many varieties of lettuce. This is one that I was most excited about. It’s called ‘Tennis Ball.’ It is a miniature butterhead type that Thomas Jefferson loved and grew in his garden at Monticello.

 

'Shanghai Green' Pak Choy

‘Shanghai Green’ Pak Choy

 

'Purple Top White Globe' Turnips

‘Purple Top White Globe’ Turnips

 

A miniature purple carrot with legs.

A miniature purple carrot with legs.

 

Two cucumbers hanging on a makeshift  trellis. I can't remember what variety they are. This why I need to remember to take better notes.

Two cucumbers hanging on a makeshift trellis. I can’t remember what variety they are. This why I need to remember to take better notes.

 

'San Marzano' Roma Tomato. We grew three other varieties of tomatoes along with this one.

‘San Marzano’ Roma Tomatoes. We grew three other varieties of tomatoes along with this one.

 

The flower of a 'Hong Hong' sweet potato. We haven't harvested these yet, so we're not sure what we're going to get. Sweet potatoes are not commonly grown in southern Idaho, so we're anxious to see how they do.

The flower of a ‘Hong Hong’ sweet potato. We have not harvested these yet, so we are not sure what we are going to get. Sweet potatoes are not commonly grown in southern Idaho, so we are anxious to see how they do.

 

We grew lots of flowers, too. 'Black Knight' scabiosa (aka pincushion flower)was one of our favorites.

We grew lots of flowers, too. ‘Black Knight’ scabiosa (aka pincushion flower) was one of our favorites.

 

Some flower's we grew specifically for the bees, like this bee's friend (Phacelia hastate).

We grew some flowers specifically for the bees, like this bee’s friend (Phacelia tanacetifolia).

 

We grew other flowers for eating, like this nasturtium.

We grew other flowers for eating, like this nasturtium.

 

Even the cat loves being in the garden...

Even the cat loves being in the garden…

It has been an incredible year. “Abundant” is the best word that I can think of to describe it. We have learned a lot through successes and failures alike, and we are anxious to do it all again (and more) next year. Until then we are getting ready to settle in for the winter – to give ourselves and our garden a much needed rest. For more pictures and semi-regular updates on how our garden is growing, follow Awkward Botany on tumblr and twitter, and feel free to share your gardening adventures in the comments section below.

Overwintering Lettuce

I overwintered some lettuce, and so can you. Below freezing temperatures usually mean the end of the growing season for most things, but certainly not for everything.  The truth is that salad greens (lettuce, spinach, kale, etc.) can be overwintered, especially if you grow them under a cold frame or hoop house or in an otherwise protected location. Some can even be harvested throughout the winter if the conditions are right.

Last fall I had nine lettuce seedlings that I had started indoors. I transplanted them outside in either late October or early November (memory isn’t serving me right now). I placed some straw mulch around them, and then covered them with a makeshift cold frame made out of PVC pipe and floating row cover. There they remained all winter long.

IMG_0740

I live in Boise, Idaho. The winters here are relatively mild (compared to the rest of Idaho), but we still have plenty of days with below freezing temperatures. Our frost-free growing season is about 160 days long. The average low temperature from December through February is around 25° F. This past winter, our lowest temperature (according to Weather Underground) was -7° F, and we had at least 30 days in which the low temperature reached 20° F or lower. Needless to say, it was a chilly winter.

But my lettuces held on…at least most of them. When I uncovered my cold frame in early March, I found that six of my nine lettuce seedlings had survived. It didn’t surprise me that a few had perished – some of the seedlings that I had transplanted were quite small, and I had serious doubts that they would make it. I was satisfied to see that the majority of them were still alive. Two-thirds ain’t all that bad.

IMG_0743

The varieties that I planted were “Freckles” and “Winter Density.” I chose these because the descriptions I read gave me the impression that they were ideal for overwintering. But descriptions be damned. I suggest seeing for yourself. Take any variety of lettuce or other salad green and experiment in your own garden. See what you can get to overwinter with or without protection. Seeds are fairly inexpensive, and it is worth seeing what you can get to survive through the winter. Differing climates – both macro and micro – will produce varied results, and every year things will be a little different. This is one of the many joys of gardening. Weather and climate will always be factors, but they can also be markers to help us see what we can get away with. And if one of the things you get away with is getting lettuce to survive a harsh winter, it means you will be eating garden fresh lettuce long before your neighbor.

IMG_0745

Winter Interest

We are well into winter in the northern hemisphere, and the plants in our landscapes have been dormant for weeks now. Trees and shrubs have dropped their leaves, grasses have gone brown, and perennial forbs have died back – their roots harboring the food they will need to return to life in the spring. What little green that is left is provided mainly by evergreen trees and shrubs, but even they are resting – metabolizing slowly and putting off further growth until warmer temperatures return. The view outside may appear largely bleak and dreary, but there is still beauty in a frozen landscape, and much of that beauty is provided by the same things that brought color and interest during the warmer months.

Many plants, though appearing dead, remain attractive throughout the winter. From fruits and cones to seed heads and seed pods, there are various structures that remain on certain plants even after leaves fall that provide winter interest. Deciduous trees and shrubs show off their branches in the winter months, which when freed from the camouflage of leaves are like sculptures – art pieces in their own right. Perennial grasses can continue to provide structure to a garden bed when left in place and upright, and color is provided by evergreen foliage and colored bark, such as the red and yellow bark of some dogwoods (Cornus spp.).

Beauty surrounds us, even in unlikely places. Things are quiet and frozen now, and foggy, dismal days abound. But winter won’t last forever. Plants can remind us of that. In them we find remnants of brighter days and an assurance that there are more to come.

alnus viridis

Male and female cones on Sitka alder (Alnus viridis)

ericameria nauseosa

Seed head on rubber rabbitbrush (Ericameria nauseosa)

SAMSUNG

Flower stalks on strict buckwheat (Eriogonum strictum)

sorbus scopulina

Cluster of berries on Cascade mountain-ash (Sorbus scopulina)

maclura pomifera

Ice crystals on the branches of young Osage-orange (Maclura pomifera)

rosa pisocarpa

Rose hips on cluster rose (Rosa pisocarpa)

sedum sp. seed head

Seed head on showy stonecrop (Sedum telephium ‘Autumn Joy’)

All photos were taken at Idaho Botanical Garden in Boise, Idaho.

Rosemary Christmas Tree

In the spirit of the holiday season, consider this fun alternative to a conventional Christmas tree. Rosemary (Rosmarinus officinalis) is an herbaceous, evergreen shrub or subshrub and is commonly found in herb gardens. Its leaves are valued for their myriad culinary and medicinal uses. Futhermore, this plant takes very kindly to pruning and shaping, which makes transforming it into a miniature Christmas tree a very simple task.

It may be too late to cultivate a “tree” for this year’s holiday season, but perhaps you’d like to try for next year. To do so, find a small rosemary plant at a local garden center or plant sale in the spring. Make a few initial pruning cuts to select a leader or leaders. After about a month or two, start giving it the shape of a Christmas tree. Floral scissors work great for making these cuts, and you don’t have to worry about where on the branches you are cutting – rosemary is very forgiving – just make sure your scissors are sharp. Wait a couple more months and then do more shaping with the pruning scissors. Do some final shaping a month or so later. At this point, you should be entering the holiday season and your rosemary Christmas tree will be ready to display. It’s that simple!

1

Initial pruning: selecting the leaders

2

Second pruning: giving it shape

3

Third pruning: keeping in shape

4

Final pruning: clean it up and present it  

One major downside to growing rosemary if you live in a cold climate is that it is only hardy to about USDA zone 7. However, if you select the right cultivar, place it in a protected location (near the south facing wall of a building perhaps), give it some mulch and maybe a blanket for the winter, you might be able to get it to survive in colder zones. Rosemary can also be difficult to overwinter indoors because the air in homes is typically dry and warm and there is little direct sunlight. If you are determined to keep one alive despite your odds, awaytogarden.com provides an excellent tutorial about overwintering rosemary both indoors and out.

Overwintering Carnivorous Plants

I once assumed that all carnivorous plants were tropical. I’m not sure exactly why. Perhaps it’s because they are so bizarre (both in their appearance and behavior), nothing like the plants that I was accustomed to seeing growing up in the Intermountain West. Or maybe it’s because the one carnivorous plant that I was most familiar with, the Venus flytrap, is commonly sold in the houseplant section of department stores. If it’s a houseplant, it must be tropical, right?

Eventually I learned the truth. Much to my surprise, there are numerous carnivorous plants that are native to temperate regions – in fact, carnivorous plants can be found on every continent except Antarctica. Even more surprising, Venus flytraps are temperate plants! It’s true. They are native to a small region in North Carolina, within about a 100-mile radius from Wilmington.

Plant species native to temperate regions require a dormant period. In the winter, the temperature drops, day length decreases, and, in some cases, drought ensues. During this time plants go dormant – they hibernate – and wait for the warmer, brighter days of spring to continue on with their metabolic and reproductive processes. It’s a period of rest.

Carnivorous plants native to temperate regions fall into this category – they require a period of dormancy in order to stay healthy and productive. In his book, The Savage Garden, Peter D’Amato asserts that, “Dormancy in carnivorous plants that require it must be respected and permitted to occur. Otherwise, the plant may die.” He goes on to say that a Venus flytrap grown year-round in a warm environment exposed to grow lights for the majority of the day “will eventually get sickly and die.” In short, these plants need a rest, and so it’s best to grow them outdoors where they will be exposed to the elements, thereby entering a period of dormancy as nature intended.

Venus flytraps (Dionaea spp.), North American pitcher plants (Sarracenia spp.), and serveral species of sundews (Drosera spp.) can all be grown outdoors year-round in temperate climates. In order to ensure their survival, it’s best to give them a little protection during the winter months – especially when temperatures are projected to reach below 20 degrees for several consecutive nights.

Recently, I helped put the carnivorous plant display at Idaho Botanical Garden to bed for the winter. The carnivorous plants are being grown in an old stock water trough. First we cut back the plants, reducing their size by at least a third and being especially careful to remove dead or rotting plant material. Next, we placed several straw bales around the sides of the trough. Then we covered the plants with three layers of material: black plastic, evergreen boughs, and dead leaves. Dave Nelson, of killergarden.com, suggests a similar winterizing treatment: “the plants can be placed on the ground, covered with a tarp, and then covered with six inches or so of dead leaves, pine needles, straw, or other mulch.”

After the threat of freezing temperatures has passed, the plants can be uncovered. As temperatures continue to warm, the plants will awake from their dormant state and prepare themselves for another spectacular season of devouring bugs and looking awesome.

IBG_carnivorous plants_fall

Carnivorous Plant Display at Idaho Botanical Garden

IBG_carnivorous plants_winter

Winterized Carnivorous Plant Display

A final word from Paul D’Amato: “You should never force a carnivorous plant into growth during a season when it should be resting.”