Drought Tolerant Plants: Water Efficient Garden at Idaho State Capitol Building

water efficient garden sign

As drought and threats of drought continue in the western half of the United States, as well as in many other parts of the world, people are increasingly looking for ways to use less water in their landscapes. For many it is a change they are reluctant to make, worried that they will have to sacrifice lush and colorful yards and gardens for drab, dry, gray, and seemingly lifeless ones. Not so, though. The palette of plants that can survive in low water environments is actually quite diverse and contains numerous plants that are just as lush and colorful as some water hogging ones. If planned, planted, and maintained well, a water efficient garden can be incredibly attractive and can even consist of some plants that are comparatively more heavy water users. So, for those who are apprehensive about getting down with brown, don’t fret – there is a better way.

How does one go about creating such a garden? The answer to that is a book on its own – much too long for a single blog post. It also depends who is asking the question, or more specifically, where they are asking it from. Luckily, demonstrations of water-wise gardens are becoming more common. These gardens, planted with regionally appropriate plants and showcasing various water-saving techniques, are great places to start when looking for ideas and motivation. Such gardens can be found at public parks, city and state government buildings, botanical gardens, nurseries and nursery centers, and water company offices. If you are looking to transform your landscape into a more water efficient one, seek out a demonstration garden in your area. It’s a great place to start.

There are several such gardens where I live, one of which is the Water Efficient Garden at the Idaho State Capitol Building in Boise, Idaho. This garden began in 2010 as a partnership between United Water Idaho and the Idaho Capitol Commission. Its mission is to introduce visitors to “low-water native and adaptive plants that thrive in Idaho’s climate.” The plants that were selected for the garden are commonly found at local garden centers and nurseries – an important objective when introducing people to water-wise gardening. The ultimate goal of this garden is to “show homeowners that they can maintain attractive landscaping while conserving water.”

I have my criticisms of this garden regarding plant selection, design, etc., but I’ll spare you those details. I also don’t know the specifics about how this garden is maintained or how often it is watered. All that aside, I am just happy that it exists, and I encourage you to seek out similar gardens in your area. There are numerous approaches to designing and constructing water efficient gardens – again, a book on its own – but demonstration gardens like this are an excellent place to get ideas and learn what other people in your area are doing to conserve water and create landscapes that better reflect the ecology of your region.

United Water Idaho offers a brief introduction to low water gardening here, as well as a list of plants that are in the capitol building garden here.

Blanket Flower (Gaillardia x grandiflora 'Goblin') Plants in the garden are accompanied by a sign with a number on it. The sign corresponds to the plant list that is provided at the entrances to the garden.

Blanket flower (Gaillardia x grandiflora ‘Goblin’). Plants in the garden are accompanied by a sign with a number on it. The sign corresponds to a plant list that is provided at the entrances to the garden.

Dianthus sp.

Dianthus sp.

Coreopsis sp.

Coreopsis sp.

Geranium sp.

Geranium sp.

Liatris sp.

Liatris sp.

A drift of pearly everlasting (Anaphalis margaritacea)

A drift of pearly everlasting (Anaphalis margaritacea)

Purple coneflower (Echinacea purpurea)

Purple coneflower (Echinacea purpurea)

Yellow ice plant (Delosperma nubiginum)

Yellow ice plant (Delosperma nubiginum)

Other “Drought Tolerant Plants” Posts on Awkward Botany:

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Drought Tolerant Plants: Prickly Pears

In the introduction to this series about drought tolerant plants, I defended water efficient gardens by claiming they don’t have to be the “cacti-centric” gardens that many visualize upon hearing terms like “xeriscape,” “water-wise,” and “drought tolerant.” And this is absolutely true. However, that won’t stop me from suggesting that such landscapes include a cactus or two. Despite their menacing and potentially dangerous spines, they are actually quite beautiful, and a cactus in bloom is really a sight to behold. Together with a variety of grasses, herbaceous flowering plants, and shrubs, cactus can add unique forms, textures, and focal points that will enhance the look and function of a water-wise garden. This is why I recommend considering cactus, particularly (as far as this post is concerned) one of the many varieties of prickly pears.

The cactus family (Cactaceae) has a native range that is limited to the Americas. Within that range it is expansive, and cactus species can be found in diverse regions from Canada down to Patagonia. The genus Opuntia (the prickly pears) is the most widespread of any genus in the cactus family consisting of at least 300 species found throughout the Americas. Even a brief investigation into Opuntia will reveal that there is considerable controversy as to how many species there actually are and what to call them. This is partly due to the large ranges that species in this genus can have and the diverse habitats they can be found in within those ranges, resulting in a single species having many forms, varieties, and/or subspecies. Hybridization is also common in this genus where ranges overlap, augmenting the challenge of identification.

Generally, prickly pears have flattened stems with spines and glochids emerging from small bumps called areoles. Their flowers are large, showy and a shade of either yellow, orange, or pink and sometimes white. They form fruits that are either fleshy and juicy with a red or purple hue or hard, dry and a shade of brown or tan. The flattened stems are called pads or cladodes and can be quite large in some species, while diminutive and sometimes rounded in others. Some species are without spines, but all have glochids – tiny, barbed, hair-like structures found in clusters on the stems and fruits. While the spines can be painful when they penetrate skin, the glochids are far more irritating as they easily detach themselves from the plant and work their way into the skin of their victims. The fleshy fruits, called tunas, can be eaten after first taking care to remove the glochid-infested outer layer. The young stems of many species can also be eaten – they are referred to as nopales and are common in Mexican cuisine.

Flowers of Opuntia sp. with bee inside flower on the left

Flowers of Opuntia sp. with bee inside flower on the left

Again speaking generally, prickly pears are very easy to propagate and cultivate. Their two main preferences are full sun and well-drained soil. If you are worried that the soil you are planting them in is going to stay too wet for too long, amend it with some gravel. This is especially important if you live in a climate that receives lots of precipitation or that has cold, wet winters. Once established, prickly pears will move around the garden. If that becomes a problem, expanding plants are easily pruned and traveling plants are easily removed.

I live in a climate that requires the selection of cold hardy prickly pears, so I am taking my specific recommendations from two books: Cacti and Succulents for Cold Climates by Leo J. Chance and Hardy Succulents by Gwen Moore Kelaidis. If you live in a warmer climate, your options will be greater. Still, the options for cold regions are pretty numerous, so for the sake of space I am narrowing my list down to a handful that stand out to me at this particular moment.

Three eastern United States species of prickly pears (O. compressa, O. macrorhiza, and O. humifusa) are, according to Chance, “more capable of dealing with wet and cold conditions than almost any other members of the cactus family.” They still require well-drained soil though. An appealing trait is their large, juicy, red fruits that can add garden interest in late summer and fall. Opuntia engelmannii is another species with the potential to tolerate cold, wet conditions. Its size is appealing to me, with pads that reach a foot wide and plants that grow several feet tall. Chance advises finding “a clone that is known to be cold tolerant” and making some space for it, “as it becomes huge in time.” The most cold tolerant prickly pear may be Opuntia fragilis. It is a diminutive plant with a large native range and a variety of forms, some with rounded pads “shaped like marbles.”

Fruits ("tunas") of Opuntia engelmannii - photo credit: www.eol.org

Fruits (“tunas”) of Opuntia engelmannii – photo credit: www.eol.org

Opuntia fragilis 'Frankfurt' - photo credit: wikimedia commons

Opuntia fragilis ‘Frankfurt’ – photo credit: wikimedia commons

Opuntia polyacantha is a prickly pear native to my home state, Idaho. It is found at high elevations throughout the Intermountain West and is also found on the Great Plains. It has many forms and varieties, and its flowers are various shades of pink or yellow. It is a fast growing species and spreads around easily. Other cold hardy species include Opuntia macrocentra (which has a very attractive yellow flower with a red-orange center), Opuntia erinacea (commonly known as hedgehog prickly pear for its abundant, long spines that can obscure the pads), and Opuntia microdisca (a tiny Argentinian prickly pear with pads that barely reach an inch across but, as Chance says, “works very well in a dry rock garden with other miniatures”).

Pads of Opuntia polyacantha

Pads and spines of Opuntia polyacantha

A post about Opuntia could go on indefinitely due to the sheer number of species and their diverse forms and attributes. This is meant merely to pique your interest. The flowers, if nothing else, should certainly interest you. In her book, Kelaidis calls them “improbably beautiful,” and goes on to say that they are “often papery, always glistening and showy.” Chance likens them to “any fancy rose” because they are “extraordinarily large, brightly colored, [and] eye catching.” Next week, as part of Awkward Botany’s Year of Pollination, I will present another reason to be fascinated with the flowers of Opuntia. For now, I will leave you to ponder this word, “thigmonasty.”

Want to learn more about prickly pears? Check out Opuntia Web.