Easy-care ground covers that grow in full sun
There are a number of plants that thrive in the Houston area
Q: What low-care/low-water ground covers will grow and flower in full sun? Carlos Rios, Galveston
A: Years ago on a Galveston visit, I was introduced to wedelia, a lush, dark-green ground cover heavily sprinkled with cheery yellow, daisylike blooms. Since that time, I have seen the perennial growing effortlessly in Houston gardens and sunny esplanades. Keep the soil moist while newly planted roots establish. Once wedelia has filled the desired area, trim as needed to keep it contained to the desired area.
The more disease-resistant vincas (periwinkles) such as the Cora series, provide months of medium-green foliage and pinwheel-shaped blooms in various colors. These annuals will persist in mild winters in Houston and Galveston. Several reseed.
I use prostrate rosemary as a tough ground cover in sun and well-draining areas. Mature plants are 2 feet tall and 3 or so feet wide. The tiny blue blooms are charming; the needlelike foliage release a wonderful fragrance when touched. And, of course, you’ll have plenty of soft foliage to flavor various dishes and oils.
If you want a ground cover to double as a deterrent, carissa, or dwarf natal plum, is about 3 feet tall, tolerant of the salty coastal air and hardy to about 25 degrees. The spiny shrub has glossy dark-green foliage and fragrant white spring flowers followed by red-purple fruit.
Serissa, a small, low-demand shrub, provides a mound of dense, tiny dark green or greenand-white variegated foliage and teeny white or pink flowers, depending on the cultivar. I trim any leggy shoots to maintain a tidier mound.
If you’ve not considered the various lantanas, you might check out these spreading, low shrubby perennials with butterfly-attracting clusters of tiny blooms in numerous colors. These perennials also tolerate salty conditions.
I’ll never tire of the stunning display of wispy pink Gulf Coast muhly grass blooms in late summer/early fall. A mass of these grasses with their gracefully attractive, 2- to 3-feet-tall mounds provides an extra-lowmaintenance ground cover. Cut back just before new growth in spring.
Q: I have thick clover in some flower beds, so I hit them with a highnitrogen fertilizer. I did this a couple of years ago in a different bed, and it seemed to help. Well, this time it appears to have turbocharged the clover. Perhaps earlier I applied it in a different season.
First question: Was the nitrogen fertilizer a mistake? And second, is there a remediation I can perform? Buz Smith, Houston
A: I believe that’s oxalis in your emailed photo. I’ve not heard of treating unwanted oxalis with a fertilizer. I would expect it to do as it did in your bed — grow even more vigorously. While there are a couple of more “desirable” oxalis types, various other oxalis species can become major pests in many gardens, multiplying by seed and bulblets. Oxalis pink, white or yellow flowers are pretty. So is the shamrocklike foliage that folds at night or on cloudy days. But several oxalis species can become incredibly invasive and highly visible during the cool months, as your photo shows.
Unfortunately, efforts to eliminate it can be a headache. Especially for those who see any oxalis as a “weed.” These cool-season, broadleaf perennials go dormant when it gets hot, so get rid of as much as possible while it’s still visible. Perhaps your earlier nitrogen application was as the oxalis was entering dormancy.
Dig out as many of the bulblets as possible. Repeat as necessary. Apply a 2- to 3-inch layer of mulch to discourage/slow oxalis spreading in your garden beds.
You might try spot sprays with a 20 percent vinegar herbicide, but be careful not to spray wanted plants.
Q: We had several Encore azaleas die this year, and I recently found the shrubs discounted at a local nursery. Since we need to replace them, we bought new ones. Should we go ahead and plant, or leave them potted and replant later?
Several of the replacements are on the west side and get direct sun.
A: Repeat-flowering “Encores” tolerate a good bit of sun and even bloom better with some extra rays. However, if they are in full afternoon summer sun, you will need to pay close attention to watering. Shallow azalea roots dry out quickly. Water to maintain a consistently moist soil (but not soggy), especially when it’s hot and dry. Mulch to conserve soil moisture and moderate soil temperatures.
The roots of azaleas planted in morning sun and afternoon shade or filtered sun won’t be as moisture needy.