Summertime in Texas is a unique gardening season. Here we have some perennials like peonies and bleeding hearts that go completely dormant and others that hunker down and quit blooming 'til fall; annuals that won't reseed again until next spring (no matter what the seed packet says about blooming "all summer long"); and then some sensational heat lovers, both annual and perennial, that save the day from June until the first frosts. Keeping this in mind, what can we do for our beds while we still have gorgeous weather to enjoy the garden in?
First take a look at your spring blooming annuals. Have you saved all the seed you wanted? Though larkspur, nigella and poppies self-sow, you'll get the colors you want, where you want, by saving seed, storing it in a cool, dry place and scattering it in the fall. Pull up or chop off the last flower stalks, making room and sunlight for any perennials that are emerging. Check on and thin your summer annuals like zinnias, cosmos and marigold which should be off to a good start by now.
Cut off the old bloom stalks of iris, oxeye daisies, and other spring blooming perennials. Usually snails and roly-polys have finished off the foliage of spring bulbs, but if not, you can neaten up your beds by cutting them back. At the same time, mark their location so that you don't inadvertently dig into them, assuming it's an empty spot, when adding a flower to the bed later on. Bulbs that keep better in storage than in the ground, like cyclamen, tulips and freesia, should be dug and brought in.
If your verbena has been blooming hard since early spring, it will benefit from a trimming. Shrubs like Anthony Waterer spirea and Salvia greggii will be slowing down in the heat but you can freshen them up and get a few more blooms by shearing them - on the Anthony Waterer, try to cut the spent blooms only, while the greggii can be taken back by a third or to shape. Though most roses slow down in the summer, dead heading will continue to encourage bloom.
If we've had a wet spring, snails and slugs will be a problem in the flower bed. There are many antidotes for these critters but none are as successful as kids. Get your children to collect them in coffee cans and pails, making sure they turn in all their findings and don't go off to play with them under the rose arbor. In the absence of kids, just go out first thing in the morning - it's a good excuse to be out in the nicest time of day - and run your fingers through the leaves of your day lilies. You will be able to pull snails off by the handfuls. Then walk through the garden, weed a bit and pick snails and slugs here and there as you find them. While you are at it, go back and check the day lilies for aphids as well, as you don't want them weakening your plants just as they are starting their yearly show. A daily blast from the hose will knock the aphids back or you might also use a very diluted soap spray.
If you're adding new perennials to your beds this summer, remember that starting plants going-into-the heat is not as easy as starting them as the weather cools down. The best plant choices will be the heat and drought tolerant ones, remembering that even these will need some water to get established.
Now, how can we help our plants help themselves in the heat? Water, mulch and compost! Hot soil temperatures burn up nutrients, so our soils in the South need organic matter more often than cool soils do. Much of your summer fertilizing can be accomplished by foliar spraying, but a good handful of compost per blooming plant, early in the summer, starts plants off right and saves doing it in the heat later on.
How do you water your beds? Sprinkler systems can be set to water lightly, deeply, frequently or infrequently, but do all of your flowers have the same water requirements and is overhead water the best for your plants? If you have good, well-drained soil (which most of us do not), watering to keep your water-lovers in bloom may not hurt their more drought tolerant companions but it isn't going to help them either. In addition, some plants like phlox are very susceptible to mildew when they are watered overhead. Soaker hoses will eliminate the problem of mildewed leaves, but unless placed so that they bypass drought tolerant flowers, deliver equal amounts of water to everything within a foot either side of their path. Drip systems can be set up to supply each plant with its approximate requirement and although they look complicated, they are easy to set up - kind of like "tinker toys." With a regulator to equalize pressure over the entire system and a good filter, "drip" is an almost fool proof way to water. Look at your watering situation, if you already have a sprinkling system in place, perhaps you could move your wet plants to one area where they can be watered separately from your drought tolerant ones. If you want to set out soaker hoses or a drip system, get it in place now and test it before adding mulch so you can see if it is reaching all areas with the right amount of water.
Another consideration is water quality. The chlorine in city water is not beneficial to the soil. Unhealthy soil makes less than healthy plants and less than healthy plants are more likely to be adversely affected by the heat. Unchlorinated well water is much better but often contains so many minerals that it can clog soaker hoses and drippers. A short-term (long-term being a rain water system) and simple last minute solution is a water filter for your yard this summer.
Last of all comes mulch. In winter we mulch to protect roots from freezing. In summer, we mulch to keep our plant roots cool. Mulch comes in many forms: shredded bark, sawdust, shredded newspaper, straw and even compost can be used as mulch. The big difference is how they look ("beauty is in the eye of the beholder") and how quickly they break down. If you want to put your mulch on once and not have to worry about it the rest of the summer, get big bark nuggets as opposed to straw which has to be added often (but also puts organic matter into your soil as it decomposes). If you have a weed blocking material on your bed, check to see if it needs to be replaced before you apply mulch. This block, when combined with deep mulch, will save you summer weeding time and is worth the expense if you're fighting something serious like Bermudagrass. Keep in mind that it's not 100 percent effective and makes adding compost and new plants difficult. Nestle mulch around the base of each plant to a depth of at least 4 inches depending on the density of the mulch material (straw would be a foot deep by comparison), if you want to insulate from the heat and keep weeds down.
Now, you're ready to get a glass of tea, lean back in your lawn chair, and watch your garden bloom.