Weekly Express-News Article

By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist

Saturday, March 29, 2008

 “Foundation Shrubs”

            Among the most important features of a landscape are the small foundation shrubs.  The idea is to transition your house to the lawn or other groundcovers, hide architectural problems and spotlight architectural assets.  In simpler terms, you want shrubs around the base of the house that compliment the house.  The shrubs you select should have a final size that covers the foundation, but does not cover the windows or the front door.  You also want shrubs that can prosper in the light and soil conditions available around the foundation.  Quite often that means the shrubs must have shade tolerance.  Here are some shrubs to consider.  It is a good time to plant them. 

 

            Dwarf yaupon holly is among the most versatile foundation shrub.  It is a disciplined grower that forms a globe that eventually reaches 5 feet on a good site, but often grows quickly to about 3.5 feet where it stays for a long period of time.  Dwarf yaupon holly is a good xeriscape shrub that has shade tolerance.  The leaves are oval, dime size, blue green, and evergreen.  There are no sharp points on the leaves of dwarf yaupon holly and no pests seem to bother it, including deer.  The shrub generally grows well in our alkaline soil and if it shows some chlorosis it will grow out of it or a little chelated iron can be added to the area around the plant. 

 

            Dwarf burford holly is another excellent foundation shrub.  It has a more upright conformation than dwarf yaupon holly and reaches 6 feet tall (eventually) and about 3 feet in diameter.  Dwarf burford holly does have a sharp point on the end of the dark green leaf.  The point does not have a blood letting sharpness, but is noticeable. The leaves are shiny and the shrub looks especially good through the winter when it is decorated with the red berries that form.  As spring nears, mockingbirds, cedar waxwings, and cardinals will eat the berries. 

 

            Dwarf burford holly is not as likely to show chlorosis due to an available iron shortage in our soils, but occasionally they will be attacked by seale insects.  In my neighborhood, the deer will eat burford holly during a droughty summer.    

 

            Dwarf Chinese holly has kelley green foliage and more serious spines than the other two dwarf hollies described.  It is thorny enough to resist the deer in my neighborhood.  Dwarf Chinese holly forms a mound that reaches 3 feet tall and 3.5 feet in diameter.  All the foundation hollies form compact plants, but dwarf Chinese holly is the tightest growing.  Like yaupon holly it sometimes has trouble with iron and shows chlorosis.  Treat it with iron chelate or a pail of compost enriched with a cup of iron sulphate every year. 

           

            Dwarf pittosporum is pretty in the nursery and has good shade tolerance, but unfortunately it suffers from a dieback caused by a bacteria like organism that kills whole stems every year.  Because of this, so far untreatable disease, I do not recommend dwarf pittosporum. 

 

            The small Indian hawthorns make an attractive mound for a few years, but then they contract a leaf spot that causes leaf drop and decline.  Use them in the sun in a well spaced configuration (good air movement between plants) for a low shrub that blooms attractively in the spring. 

 

            Boxwoods are a favorite shrub for many applications because they grow fast, are inexpensive, and can be pruned to any shape. The deer also do not eat boxwood.  Although there are some attractive boxwood hedges I do not recommend them for a foundation planting because they seem to require more pruning to look good, are bothered by dieback, become leggy in the shade, and are a favorite scale host. 

 

            It is a good idea if you have a foundation planting to water them by means of a drip irrigation system or a leaky hose.  Put a drip emitter right at the base of each plant.  Hollies are very drought-tolerant, but they are slow to put out a root system.  For the first two summers they need to be watered at the base every week for best performance.