Q: The southeast corner of my house next to the cement foundation is very hot and dry. Wide eaves keep most rainwater off the area. Could you recommend some shrubs or shrubby perennials that can take the heat and drought there? — Judith Rudolf, Milwaukee, WI
A: Whatever you plant against your foundation should naturally stay low. Shrubs, especially evergreens, are traditionally used as foundation plantings, but most quickly grow too big. They make it impossible to maintain your siding or roof gutters properly and eventually will block doorways or the view from a window. The plants I recommend stay less than a foot tall without any trimming or shearing; they are often referred to as ground covers. Technically, some are shrubs and some are perennials.
For your hot, dry spot, my top choices are the lowest-growing junipers you can find. These evergreen shrubs can, in truth, be either green, bluish, or gold tipped, and some even take on purplish tones in winter. My personal favorite is Juni-perus procumbens ‘Nana,’ which has a soft, mossy, mounded appearance and stays well under a foot tall. Equally good are cultivars of J. horizontalis, which grow perfectly flat along the ground. Look for either ‘Blue Rug’ or ‘Bar Harbor.’ Or try a pair of the so-called broad-leaved evergreens. Actually, their leaves are tiny, not broad, but these plants look good year round, with shiny foliage and colorful red berries in winter. Creeping cotoneaster (C. horizontalis) and the North American native kinnikinick (a.k.a. common bearberry or Arctostaphylos uva-ursi) are both very tough in the face of dry, hot summers and frigid winters. Almost all drought-tolerant perennials will work, since you can hack them back easily whenever the need arises without inflicting any great damage.
Creepers with leaves that retain color and form in the winter are ideal. Consider the minicarnations known as cheddar pinks (Dianthus gratianopolitanus and hybrids). They are known for their charming, fragrant flowers, but their leaves are wonderfully hardy and remain the color of a blue spruce year- ound. Plumbago (Ceratostigma plumbaginoides) will give you electric blue flowers late in the summer and bronze foliage throughout winter. Good old moss phlox (P. subulata) is a spring classic, but the foliage remains year round, becoming purplish in winter. Best of all may be the sedums. Many of the low-growing varieties like ‘Weihenstephaner Gold,’ ‘Dragon’s Blood,’ and ‘Vera Jameson’ have nice foliage color through the winter. Good taller varieties are ‘Autumn Joy’ and ‘Matrona.’
Even some herbs might work. Try gray-green kitchen sage (Salvia officinalis). And there are many good varieties of thyme with interesting foliage that lasts all year. As for taller shrubs, such as azaleas, yews, and taller junipers, I strongly suggest that you keep them considerably farther away from the house than is traditional — at least 8 feet from the foundation and maybe farther, depending on how tall your house is. The idea is to keep a clear area all around the building, creating enough space for you to walk comfortably and wide enough for you to set a ladder that can reach the roof anywhere. From a distance, your house will look comfortably nestled among the greenery, but up close you will have a private zone where you can walk, work, and enjoy a tapestry of low-growing plants.