Gardening This Weekend: August 6, 2020
I try never to give you more than the most critical and timely of tasks. He’s what I’ve put into the pile for this weekend ahead.
PLANT
• Cole crops. Set out vigorous nursery transplants, including cabbage, broccoli, cauliflower and Brussels sprouts. See related story last week.
• Fall foliage color from copper plants, firebush (also has blooms) and purple fountaingrass or fall floral color from zinnias, marigolds and celosias. You may have to look a little bit, but whenever possible buy potted transplants that are in bud but not yet in bloom.
• Dig and divide established daffodils, jonquils and narcissus before new root growth begins. If you’re going to be ordering more for planting in a few weeks, start shopping now.
PRUNE
• Salvia greggii and rose bushes by one-third to stimulate new growth. It’s on those new shoots that fall blooms will be produced.
Note to our DFW-area readers: Rose rosette virus is epidemic in and around the Metroplex. If you are growing roses in that area, check out the details I have on my website.
• Pinch or prune flowers from coleus, basil, mint, caladiums and other plants where flower buds and flowers stop production of new foliage.
• Spent flower stalks, seedheads from annual and perennial plantings to keep landscape tidy. That does not, however, include crape myrtles. Do not feel like you have to remove seed heads from them.
FERTILIZE
• Bermuda turf with all-nitrogen lawn food in which as much as half of the nitrogen is in slow-release form.
• Do not fertilize St. Augustine for another 3-4 weeks to avoid a late-season outbreak of gray leaf spot (fungus that is exacerbated by applications of nitrogen). When it’s present you’ll see diamond-shaped, gray-brown lesions on the blades, usually near the midribs. The fungicide Azoxystrobin is labeled to control it.
• Water-soluble, high-nitrogen plant food to container plants including hanging baskets. Nutrients are not retained very long with frequent irrigation and lightweight potting soils.
• Iron-deficient plants. Look for yellowed leaves with dark green veins, most prominent on newest growth first. Apply iron with sulfur added. Function of the sulfur is to acidify the soil so that the iron will remain soluble as long as possible.
ON THE LOOKOUT
• If you have nutsedge (nutgrass) in your lawn, this is almost your last call to apply Image or Sedgehammer to eliminate it. Both products need several weeks of warm soils to complete their work.
• Leafrollers are attacking vinca groundcover and several types of shade trees and shrubs, also cannas. They roll up the leaves or tie them together as protection. Systemic insecticides will stop them, but only if applied 2-3 weeks prior to their arrival. It’s probably too late for this season.
• Chinch bugs are a problem in St. Augustine again. Big areas first look dry, then dead and brown in spite of watering. Get down on your hands and knees in the hottest part of the afternoon. Look at the interface of the dying and healthy grass. You’ll probably find small black insects flitting around there. Look for irregular white diamonds on their backs. Treat with a labeled lawn insecticide.
• Gray leaf spot is common in St. Augustine and also zoysia during the hot weather. Afflicted areas have an overall yellowish appearance when viewed from a distance and you’ll be able to see the gray/brown lesions on the leaf blades when you look at them closely. Do not apply nitrogen until September to lessen its impact. The fungicide Azoxystrobin, sold at the consumer level as Scotts Disease-EX, offers control.