Express-News Weekly Column

Saturday, May 19, 2001

Submitted by Calvin Finch, Ph.D., Director of Conservation, SAWS, and Horticulturist

PLANT HOT WEATHER BLOOMING PLANTS NOW

            San Antonio is a hot place in the summertime. It is not always pleasant to be outside. If we plant some hot weather blooming plants now, however, we can admire them from inside the house when it gets really hot.

            Most San Antonio nurseries are selling one or more of the old-fashioned petunias, Kahuna, VIP, or Laura Bush. VIP is a parent of many of the hybrid petunias. Laura Bush and Kahuna are second generation. The flowers are smaller and limited in color when compared to the modern hybrids, but the plants are more aggressive and much tougher. If you prune them back every six weeks they will bloom through the summer. Laura Bush reseeds as well. Use the old-fashioned petunias in full sun beds or containers. Deer seek out the modern petunias but do not seem as interested in the stronger fragranced old-fashioned varieties.

            Periwinkles (vincas) like it hot and dry in full sun. They will bloom from now until cold weather arrives if certain strategies are practiced. The key to periwinkle performance is to avoid aerial phytophera, a fungus disease that reduces the plants to mush. The disease is in the soil so you must avoid soil splash. A 1- to 2-inch layer of mulch (leaves, pecan shells, fine bark, cypress, grass clippings, etc.) applied after planting works well. Keeping water off of the leaves also helps. Use drip irrigation or, if you must sprinkle overhead, water in the morning so the water on the foliage dries before evening.

            Periwinkle is deer proof in most situations and are a favorite of butterflies. They come in violets, white and pink.

            Caladiums provide hot weather color in the shade. They come with red-pink foliage or green-white. Some selections have colored veins. Like periwinkles, caladiums are not planted until this time of the year. They rot in our heavy soils if the soil temperature is cool. Protect caladium foliage from slugs and snails with baits labeled for the purpose or use beer traps. Sink plastic cups at several locations in the bed and fill them with ½ cup of beer. The pill bugs, slugs and snails will quickly fill up the cups with their dead bodies.

            Coleus is another foliage plant that performs well in shade in the summer. There are yellow-greens, pinks, silvery-whites, burgundies, and many bicolor or even tricolors available. Coleus also attracts slugs and snails, so be generous with the baits.

            Firespike will prosper in the deepest shade. It is a root hardy perennial that has shiny dark-green foliage, and is attractive enough in its own right to be a houseplant. In late summer, however, outdoor plants send up a spike of red blooms that are a favorite of the hummingbirds. Use firespike in a container as a patio plant for shade. Move it into the house to enjoy the foliage for the full winter or let it freeze back.

            Moss roses and purslane are low growing annuals that prosper in full sun in the summer heat. The moss roses have compound blooms in pastel shades of yellow, pink and white. Purslane has simpler flowers and more intense colors. The main problem with moss roses and purslane is that the flowers keep banker’s hours. Some of the new selections of both species bloom longer into the evening. Both moss roses and purslane make excellent container plants.

Other hot weather bloomers to consider are esperanza, firebush, poinciana, lantanas and summer salvias. All of them are root hardy perennials that perform well in full sun.

            Esperanza (yellow bells) has yellow tubular flowers. It may reach 7 or 8 feet tall in a sheltered location, but generally grows to 4 or 5 feet if it freezes back or you cut it back to the ground. Esperanza is a deer proof plant that is a favorite of hummingbirds.

            Firebush is probably the favorite hummingbird plant. Unfortunately, the deer also seem to favor it. The plant can be used as an annual to produce a two-foot globe-shaped plant covered with small, red tubular blooms. If allowed to come back each year it gets larger each succeeding season until it reaches 5 or 6 feet tall and wide.

            Poinciana (Bride of Barbados) has glow-in-the-dark orange-red flowers that attract butterflies and hummingbirds. The foliage is very airy looking on a plant that reaches five or six feet tall each year except where it does not freeze back. In South Texas the poinciana make a small tree.

            Lantana comes in two basic growth forms, spreading and bush. The spreading selections have lavender, golden, white or crème colored. The bush types have bicolored flowers that can be pink and crème, orange and yellow, or red and yellow. Lantanas attract butterflies and hummingbirds. Deer may nip at the blooms but do not eat the foliage.

            The hot weather salvias have blue flowers. They are root hardy perennials that can be very vigorous like the Indigo Spires that covers a 6-foot tall by 6-foot wide space. Mexican bush sage has a silvery foliage and is generally 3-foot high and produces a 4-foot mound. Mealy blue is another summer salvia that is readily available on the market. Salvias are attractive to hummingbirds and butterflies and are not eaten by deer.