September 2, 2002

This past week I have been asked to look at a lot samples from trees that are doing poorly. Homeowners are concerned that the trees are dropping leaves or the leaves are brown or damaged in some way. Most of the samples were from trees that are drought stressed. Many are well-established trees that were not watered except for the minimal rainfall. These trees will probably recover, but should be watered during any more dry spells from now until the ground freezes.
A natural response is to want to give these stressed trees some fertilizer to help them increase vigor. But after a prolonged drought fertilizer will do more harm than good. The roots have not received sufficient water to maintain healthy tissue- think of them as injured. Fertilizers are high in salts and can burn the damaged tissue. Increasing soil moisture will be the best thing for rejuvenating the trees root systems.
This time in the growing season the trees need to begin their preparation for the upcoming winter. Active growth should start to slow down, chlorophyll production will be less and the fall colors will begin to show. As the trees go into dormancy fertilizers should not be added. Resulting new growth will not have a chance to harden off before the freezing temperatures arrive. And more dieback will occur.
Plan to fertilize your trees and shrubs next March or April. At that time the trees will be coming out of dormancy and will be ready for a good feeding. Both evergreen and deciduous trees and shrubs should be fed in the early spring. And if the plants have been growing well, they may not need it at all.
The rain this past weekend may have put a damper on holiday gatherings but I haven't heard too many complaints. It is a relief to get much needed rainfall. Although the ground still needs a lot more water to get back to normal, we can start some yard projects.
Lawns in particular have taken a beating this summer. Many will need at least some over-seeding to fill the bare spots. Now is the time to rake up the dead patches and spread some seed. September through the early part of October is the best time to start or renovate a lawn.
Unlike the trees and shrubs, cool season grasses will be in active growth during the fall months. For that reason fertilizer can be applied, especially after the recent rains. A slow release organic fertilizer would be a good choice or one with an analysis that isn't too high in nitrogen. 10-6-4 can be used on lawns in spring or fall and is also safe to apply before seeding. There are also formulas made specifically for seeding.
Grass seed mixes for this area should include bluegrass, perennial rye and red fescue. For sunny areas use a mix with predominately bluegrass and rye. For shady areas make sure the mix has a good percentage of red fescue. Deeply shaded areas will not support grass. For those areas use a mulch to cover bare ground or try to grow a ground cover such as pachysandra.
Newly seeded areas will need to be kept moist until the grass seed germinates. After germination the seedlings should be watered a couple times a week until it is mowed for the first time.
In the vegetable garden tomatoes, peppers, and eggplant are at the height of their season. Harvest them daily at the peak of flavor. Leafy greens such as arugula, lettuces and spinach can be planted now. Plant them from seed or as seedlings. There will plenty of time to harvest them before a hard frost. They will also grow until the beginning of December with the protection of a row cover. Cover crops such as rye, buckwheat or hairy vetch can be sown in the empty spaces in the garden. These cover crops will help enrich the soil for next season's garden. They can be planted throughout the fall months.
Next spring mow the cover crop down and turn it under to break down. This is often referred to as a green manure.
The annual flowers, late blooming perennials and roses put on a terrific floral display in September. Cut large bouquets of them for arrangements indoors. Remove any foliage that would be immersed in water in the vase. Most flowers can last at least a week indoors. Enjoy these last flowers of summer this month- fall will be here before we know it.
Beth Nardone, botanist, is a resident of Hillsborough and is the Nursery Manager at the Belle Mead Co-Op. Questions and comments can be sent to bethtanical@rcn.com