The title sounds like an oxymoron and we know gardeners do love a challenge. The challenge comes in manipulating the heavy, clay soil so these desert beauties can thrive in high humidity along with periods of heavy rainfall. What is it they say about Houston weather, “Don’t like it, wait a minute and it will change!”
An arid plant naturally occurs in regions where water is scare both in the air and soil and the soil makeup is rock and sand which holds no water when it rains as runoff is quick. Plants change their physical look and makeup to adapt to their environment whether shady and wet to sunny and dry.
SOME CHARACTERISTICS OF ARID PLANTS ARE:
- Small leaves less than 1”(less water loss)
- Leaf color is gray, blue, or light green to reflect sunlight and reduce hot temperatures on the leaf surface (cooling)
- Waxy leaf surface keeps plants from transpiring (moisture loss)
- Hairy and spiny leaf surfaces slow down wind – reducing water loss.
- Fleshy tap roots allow plant to penetrate soil deeper to access pools of water.
So now you see why it is important to amend our heavy soils to grow arid plants successfully in our region. Clay soils are easily amended by using a Mantis tiller to pulverize the clay into small particles. Once you have pulverized the clay you can amend with limestone (raises the soil ph) or use expanded shale (neutral in ph). You don’t want to dig out and remove the clay, just blend the native soil 50-50 with expanded shale or crushed limestone depending on plant choice and soil type. The shale or rock creates channels in the clay soil that allow water to flow through for rapid drainage, hosts air and gas exchanges, and creates pathways for optimum root growth.
ARID PLANTS THAT BENEFIT ADDING LIMESTONE TO SOIL:
Cordia boissieri – Wild Texas Olive, white flowers in spring and doesn’t make olives.
Sophora secundiflora – Texas Mountain Laurel, fragrant purple flowers that look like wisteria and smell like grape bubblegum.
Yucca rostrata – Big Bend Tree Yucca, white flowers in spring, a beautiful architectural plant; should be poster child for dry garden plantings!
Nolina texana – Beargrass, Clumping wiry plant that doesn’t exceed 2’ tall x 2’ wide, interesting white bloom, not a true grass, it is in Lily family.
Dasylirion texanum – Texas Sotol, clumping native grows 4’x4’ and produces flower stalks that grow 9-15’.
ARID PLANTS THAT BENEFIT USING EXPANDED SHALE IN SOIL:
not only should you amend with the shale, but use the shale as mulch too!
Aloes – plant these tropical succulents in a protected exposure as they are winter bloomers.
Sedums – some sedums prefer sun, while others prefer shade, there are several hardy varieties
Graptopetalum paraguayense – Ghost Plant, Opal Plant a true perennial succulent for Houston, forms a rosette
Hesperaloe parviflora – Red Yucca is a short clumping plant that produces red flowers in early summer and hummingbirds flock to it.
Leucophyllum frutescens – Cenizo, Texas Sage is native to south Texas, so grow this one in full sun, not next to the house and rain triggers bloom period.
Scuttelaria suffrutescens – Skullcap is a great perennial for sunny, gravelly soils and flowers 10 months out of the year reaching 6-10” tall.
The best arid plant collection in the Houston area is found at Peckerwood Gardens in Hempstead, Texas. John Fairey has been collecting and planting Mexican plants since the early 1970’s and it is very interesting to see how the plants truly adapt because this property is subject to flooding. This botanical collection has over 3000 rare and unusual plants from the US, Mexico and Asia displayed throughout the 20 acres.
Time truly flies when one is immersed in learning about this exquisite plant collection, thank you Adam Black, Director of Horticulture for sharing your time and knowledge with me!
For more information check out: www.peckerwoodgarden.org