Water demands high for plants during peak of summer

By Lelia Kelly and David Nagel

Extension Horticulture Specialists


The peak of summer is a maximum growth time for plants, so their water demands are high.

Keep flower and vegetable gardens watered if it doesn’t rain for five or six days. Water early in the morning for best results.

If you have perennials or other plants that are newly established be particularly watchful to make sure these are getting the water they need.

Division of Iris

Dig up and divide crowded German or bearded iris now. Cut off two to four inch pieces of rhizomes with foliage. Trim the leaves back to 6 or 7 inches in an inverted V shape, and replant the rhizomes with their top half above the soil surface and about a foot apart. Water well after planting.

Sow Now for Fall-Blooming Annuals

Sow seeds of zinnias, marigolds, sunflowers, cleome and cosmos for a blast of color that will last until frost. All of these will flower within eight-10 weeks of sowing. Prefer to publication 2449, “Grow Your Business with Flower Garden ‘Signs,’” for more information and choices of annuals to sow.

Canna Care

For blooms all summer and neater plants, remove flower stalks as soon as the flower fade. A new stalk should grow below the old one. Also check the top leaves for signs of leaf roller larvae. Infested leaves will be twisted and rolled together. Contact insecticides won’t reach larvae protected by the leaves. You will need to hand pick and destroy these.

A foliar spray will penetrate into the plant and offer protection. Look for pesticides with the active ingredient, acephate. One brand name product to look for is Ortho Systemic Insect Killer.


Be careful applying water-soluble fertilizer that you spray on the plant. High temperatures and low humidity can change the dilute nutrient solution you are supplying to help the plant grow into a dry salt that kills leaves. Make sure the plants are well watered and apply the spray on fertilizer when dew is on the plant or after the sun is down.

Some tomato varieties are naturally slow to ripen around the stem scar. The most widely grown is Celebrity, but many varieties will have slow ripening shoulders when temperatures are high. There are two easy solutions. One is to pick the fruit with green shoulders and allow it to finish ripening is a cool place.

The other is to keep the fruit from direct sunlight. Gardeners with only a few plants may want to make shades out of paper or other light material and clip it to the plant.. The solution next year is to pick a variety that isn’t prone to green shoulders.

Pumpkin growers should be finished planting now. Those who haven’t gotten the plants started yet should look for varieties that take less than 100 days to ripen.

Big Autumn and Early Autumn are two good choices for jack-o’-lanterns since these are yellow when immature and will still be attractive even if they are not quite mature in early October. Other carving pumpkins include Pro Gold 510 and Aspen. An attractive, small pie pumpkin that is good for decorating is Pik a Pie.


Mow often enough that seed heads don’t have time to flower and mature seeds. Seeds become the user of all the carbohydrate the leaves make and the turf plant will not grow as well.