Plants for Clay Soil: Low Shrubs

As mentioned in a previous post, I’m on a quest to create a native/Mediterranean, drought-tolerant, deer-tolerant entrance to our home, with seasonal interest, low maintenance, and consideration for the garden’s Asian flavor. In this post I have compiled a list of low shrubs that can thrive in clay soil, and partial sun. Shrubs are woody plants with multiple trunks or branches growing from the base; they range from ground covers, to almost 15 feet tall.

My selections are in the Coast Live Oak tree palette, using Bob Perry’s classification in Landscape Plants for California Gardens. In nature, they are found in close proximity, and have similar requirements. Most native plants require good drainage, and typically do not require a lot of organic amendment. Here are some favorites that meet my criteria. Some are on the fringe, but might work with careful placement.

• Arctostaphylos “Emerald Carpet” (Emerald carpet manzanita) – 12” high, with 4-6 feet spread. Pale pink, urn-shaped flowers and attractive vertical leaves. Use as a low shrub with training, or ground cover. Does not like heavy clay soil. Attracts pollinators. Requires little water once established. Compatible with oak. Ericaceae family.
• A. hookeri (Hooker manzanita) – 2-3 feet high, with 4-8 feet spread. White to pale pink urn-shaped flowers. Forms dense mounds. Attracts pollinators. Requires little water once established. Compatible with oak.

Arctostaphylus hookeri ssp. franciscana (Hooker manzanita) - photo by Stan Sheps taken at the
Regional Parks Botanic Garden, Berkeley, California, taken April 2007. Creative Commons.

• Artemesia spp. (California sagebrush) – low rounded form, 2-4 feet high, with 3-6 feet spread. Silver-gray, fine textured foliage with pungent aroma, and insignificant yellow-green flowers. Compatible with oak. Asteraceae family.
• Ceanothus maritimus “Valley Violet” (Maritime ceanothus) – low mounded form, 1-3 feet high, with a 3-8 feet spread. Pale white to pale lavender flowers from February to June (dark lavender for some cultivars). Shaping can improve appearance; prune in late summer or fall. Requires little water once established. Compatible with oak. Rhamnaceae family.



Ceanothus maritimus "Valley Violet" (Maritime ceanothus) - photographer unknown.

• Galvezia speciosa “Boca Rosa” (Island snapdragon) – 3-4 feet, with 5-7 feet spread. Scarlet, tubular flowers bloom throughout the year, especially in spring. Does not tolerate frost. Shaping can improve appearance. Scrophylariaceae family.
• Gaultheria shallon (Salal) – 1 ½ feet tall, with 4 feet spread. Pink and white urn-shaped flowers April – July, and then dark blue, edible berries. Leaves have a hint of red, and branches are deep red. Use for erosion control, ground cover, hedge, or low shrub. Requires little water once established. Attracts pollinators. Ericaceae family.
• Rhamcus california “Sea view” (California coffeeberry) – 2 feet high, with 4 feet spread. Inconspicuous flowers in spring, with showy berries. Leathery, dark leaves. Dioecious. Rhamnaceae family.
• Rhododendron occidental (Western Azalea) – 3-10 feet high, with 3-10 feet spread. Delicate white bloom, tinged with pink and orange, sweet fragrance. Sometimes fussy; prefers acidic soil, so does well with organic matter. Attracts pollinators. Prefers shade, and is riparian, so requires more water (may not be a good fit). Ericaceae family.
• Rhus ovata (Sugar bush) – 4-10 feet high, with 4-10 feet spread. Reddish fruit with sugary coating, and fire-resistant dark green leaves. Can be clipped as a hedge. Compatible with oak. Anacordiaceae family.
• Rosa californica (California rose) – 3-6 feet high, with 5 feet spread. Can be kept low by pruning right after blossoming. Large pink flowers have a rose fragrance, and bloom from spring to summer; brightly colored rose hips. Attracts pollinators. Prefers full sun near the coast, or shade inland, so place accordingly. Deer eat flowers but not the leaves. Rosaceae family.

Good sources:

• Bay Natives: http://www.baynatives.com/
• The Watershed Nursery : http://www.watershednursery.com/
• Berkeley Horticultural Nursery: http://berkeleyhort.com/index.html