Keith Hansen

This time of year gives us some of the best and worst of times in gardening. Of course, summer heat and prolonged dry spells take their toll on plants of all types. But, there are wonderful plants that really strut their stuff the hotter and sunnier it gets.

The rainy spring we had promoted fungal leaf spot on some red and post oaks, resulting in early leaf drop from some trees.

Although it is stressful on trees to lose some of their foliage early, the good news is that fungal leaf spots do not produce long term ill effects on most trees.

A healthy tree can tolerate some stress, and pending the return of optimal growing conditions, a tree can rebound by the following spring with no lasting problems.

The droughts of 2005-06, then the flooded soil conditions of early summer 2007, followed by our current dry conditions, all take their toll on trees and shrubs.

These stresses may predispose weaker plants to succumb to root rots or other diseases, causing dieback or death.

Chinch bugs, a perennial summer problem for St. Augustine grass lawns, has been seen in several lawns in the region recently, so be on the lookout for drying patches in the lawn that do not perk back up after an irrigation or rain.

The recent rains have once again brought welcome relief to stressed trees, shrubs and lawns. Keep track of total rainfall amounts with a rain gauge to be sure your lawn and garden is getting adequate water. Brief rain showers may cool things off and temporarily perk things up, but may not provide enough water to penetrate the soil more than an inch or two.

Lawns, gardens and shrubs benefit much more from a thorough weekly soaking than by frequent, shallow sprinklings, whether through your irrigation system or showers.

Despite the heat, there are many wonderful plants that thrive in the summer's heat. Once again I encourage you to take a trip up to the Tyler Rose Garden and visit the IDEA Garden, Heritage Rose Garden and shade garden in between. I am really impressed with the diversity, quality, health and beauty of the plants on display there. The Smith County Master Gardeners, a trained volunteer organization of the Texas AgriLife Extension Service, do a tremendous job of maintaining these gardens, making them showplaces worthy of a special trip whether you are visiting from out of town, or a frequent garden visitor. You will usually catch Master Gardeners hard at work there on Tuesday mornings.

Zinnias are taking center stage in gardens right now. There are many varieties, from the taller growing, large-flowered types with bright and bold colors, to the more compact zinnia types that resist the common diseases that zinnias tend to get. Zinnias are native to Mexico and Central America.

One of the most successful types of zinnias in our southern gardens is the Narrow-Leaf Zinnia (Zinnia angustifolia). These are low growing, drought and disease tolerant varieties with small flowers that bloom all season long. All types of zinnias are magnets for many kinds of butterflies. Plant zinnias in full sun, and avoid overhead irrigation to reduce diseases.

One of the things I like about the IDEA Garden is you have a chance to see new and unusual plants being tested for suitability for the conditions in our area. Many are labeled, and the goal is to have most everything eventually identified to make your visit even more productive.

On the north side of the patio is a selection of some of the plants that have gone through trials in Dallas and Overton and been selected as North Texas Winners Circle winners. These are tough, beautiful and garden-worthy plants. A complete selection of North Texas Winners Circle plants is listed on the Overton web site - http://flowers.tamu.edu

One of the North Texas Winner Circle plants dominating the IDEA Garden along the grassy path is Euphorbia cotinifolia "Burgundy Wine.''

This tough annual foliage plant has dramatic foliage that holds it is dark burgundy color all summer, quickly growing to an impressive 4 to 5 feet tall in full sun. Equally impressive is the tropical annual called Variegated Tapioca with its brightly variegated green, yellow and chartreuse, fan-shaped leaves on an upright bush.

Rain lilies have been popping up here and there in East Texas, including the IDEA and Heritage Gardens, in response to the recent rains. These delightful small plants burst into bloom shortly after summer rains, giving a cheery look to any garden. White and pink are the 2 most common garden varieties, and there is a small native yellow rain lily that blooms in summer after a mid-summer shower.

Keith Hansen
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