The September Gardener

Even though the weather will be cooling and the daylight dwindling, it’s way too early to put the gardening tools away. Summer is almost over and children are back in school—it’s time to return to the garden.

It’s been a very hot (record-breaking, again) and dry summer. Many lawns have turned brown and some plants have wilted or died. With the return of cooler weather (and hopefully some rain), lawns and gardens should start to turn green again.

Tree Time: Cool fall weather provides ideal growing conditions for new trees. Buying nursery stock now is good for your pocketbook, too. Garden centers often slash prices this time of year to reduce inventories. Check to see if the tree still comes with a one-year, money-back or replacement guarantee. If it doesn’t, the discount may not be such a good deal. Plant a tree at the same depth it grew in the nursery pot and water regularly until the ground freezes. Mulch around the tree with 3-4 inches of shredded pine bark mulch.

Leaf or needle drop on shade trees and evergreens is common now and is caused by many factors typical of summer. Many shade trees are exhibiting other stress symptoms such as leaf scorching or early fall coloration (my River Birch tree has been dropping leaves since July). You may notice older leaves dropping from rhododendrons and other evergreen shrubs. This is normal for this time of year. White pine will shed older needles at this time of year.

Annuals and Perennials: You can plant hardy mums now so they can become established prior to cool weather. Pansies, ornamental cabbage and kale can also be planted. Leave the flower heads of perennials like tickseed, purple coneflower and black-eyed Susans to provide nutritious seeds for birds this winter. If you want to keep your geraniums blooming, entire plants can be brought inside and grown in a sunny window.

Lawns: Hot summer weather may have caused your lawn to turn brown and go dormant. This is a natural response that helps turfgrass survive hot and dry conditions. Grasses that go dormant should green up and grow vigorously again in the fall.

However, many people have dead-looking areas containing more weeds than turfgrass. The soil in these areas is usually compacted from foot and lawnmower traffic. These areas should be overseeded or completely renovated.

You can overseed (or renovate, which is a much larger project) your lawn from mid-August through mid-October with a turf-type tall fescue cultivar at a rate of 4 lbs. of seed per 1,000 square feet of area. Prior to seeding, the area should be raked vigorously with a metal rake to loosen the soil and promote good seed-to-soil contact.

I usually add some lawn or garden soil to the loosened soil, which also provides better seed-to-soil contact. After seeding the area, it should be watered lightly (not soaked) twice each day, even after the grass emerges. Fescue seed should germinate in about a week. Broadleaf weed killers cannot be applied just prior to or just after seeding, but they can be applied after newly seeded grass has been mowed at least three times.

This is a good time to have your soil tested. Visit the University of Maryland's Home and Garden Information Center’s website and watch the video on how to take a soil test.