GNO Gardening- October 2015

Lee Rouse, Bertrand, Sarah  |  10/5/2015 6:59:51 PM

Why do we plant trees and shrubs in the Fall?

As we transition from season to season, our beloved trees and shrubs are going to sleep for the winter, or so it seems. It appears that no growth is occurring this time of year; and that is correct if you are only looking at the above ground portion of trees and shrubs. We don’t see any new foliage growth this time of year, so it would seem that now is an unfavorable time to plant. But in fact, now is actually the best time to plant trees and shrubs.

It will prove best to plant trees and shrubs in the late fall (October- December). The reason why these plants should be put in the ground this time of year is because soil temperatures stay relatively constant and much higher when compared to the air temperatures above. Though the plant may seem to be dormant for the winter, this is only true for the part of the plant that is above the soil line. The roots of many trees and shrubs are growing during the winter but very slowly. During this time of year when only the roots are growing, they do not have to provide the above-ground portion of the tree with any nutrients or water as they would in the warmer parts of the year.

Planting in fall gives trees and shrubs an additional 4-5 months of root growth before the roots have to perform any major tasks. Because the roots have time to spread out in the soil, this will help to ensure their success in the garden. This is due to the fact that with the more roots present, the more the plant is able to take water up during our dreadful summers. On the contrary, if we were to have planted the same plant in spring, this plant would have very little time to put out roots before the scorching hot summer comes along. Also, the strain of supplying needed nutrients and water to the rest of the plant for it’s new growth will take a toll.

Planting trees and shrubs in fall or early winter will be much better for our gardens due to having a larger amount of roots. Though there may be greater root mass we still need to be conscious of watering for the first year or two. A better root system means that we, as gardeners, will not have to be out in the yard as much hand watering thirsty plants. So get your trees and shrubs planted now in the fall and enjoy the ease of gardening in the summer. - Lee Rouse

Fall Planting Guide



Snow Peas


Swiss chard

Broccoli (transplants)




Brussels sprouts (transplants)




Cauliflower (transplants)


Leaf lettuce




Chinese cabbage




Green Peas








Chinese Forget-me-not




Sweet alyssum





Sweet peas





Wall flower

Large Patch Lawn Disease
A.K.A. Brown Patch

We love the fall… and so does the fungi Rhizoctonia solani, which you may know better by the common name of the disease it causes in our lawns, brown patch (or large patch). This fungus thrives when temperatures are between 60ºF and 75ºF, especially when moisture is present. The result of this fungal infection will be, as the name suggests, a patch of dead grass in your yard. Infected areas of St. Augustine will turn yellow and then die, and the individual blades of grass will be rotten or water-soaked at the base. This disease is most severe in St. Augustine grass, although it can infect other warm-season turf grasses as well.

So, what can we do about this unsightly disease? First of all, keep your lawn in good health by providing full sun, monitoring moisture levels, increasing air flow through your yard, dethatching and aerating as needed in the spring, and fertilizing appropriately. Avoid over applying nitrogen in the summer months, and never apply nitrogen fertilizer this late in the year. It is common for homeowners to pick up a bag of  'winterizer' fertilizer because it’s sold at the hardware stores, but it will only be beneficial if your soil is potassium-deficient. Check your ‘winterizer’ fertilizers before applying, as many of them will contain nitrogen along with the potassium you want. High nitrogen levels, as well as thatch and watering late in the day, encourage this disease. If you have had problems with brown patch in the past, you are likely to see problems again this year, but the damage can be mitigated with a preventative, granular fungicide application. If brown patch is already developing in your lawn, apply any liquid fungicide from your local nursery that is labeled to control this disease as soon as symptoms appear - Sarah Bertrand

Volunteer Spotlight:
Lydia Pollard
Lydia has been volunteering as a Louisiana Master Gardener since 2012. She is the project leader for our ARC Uptown Cut Flower and Perennial Garden project, working with ARC staff and participants to enhance their lives through horticulture education. She also teaches horticulture to students and teachers at Audubon Charter School, through their school butterfly garden. Lydia coordinates the greenhouse which supplies plants for Master Gardener projects and plant sales, and she has volunteered hundreds of hours each year.

Plant of the Month:
Bald Cypress Taxodium distichum

Louisiana state tree
Mature height = 100-120 feet
Mature spread= 25-50 feet
Deciduous tree that looses its leaves during the winter
Fast growing for the first 10 years
Most abundant in wet swampy soils
Can grow "knees" from the roots when submerged or in poorly drained soils

Pest Alert:
Taxodiomyia cupressiananassa

The cypress twig gall midge, Taxodiomyia cupressiananassa, infests bald cypress trees causing them to form galls from the leaf buds. The larvae of the insects grow and develop inside of these galls. Although the pest does not actually harm the tree, they can reduce its appearance. The galls will fall off in the fall and the new adults will emerge from them in the spring. The best control measure is to pick up and destroy the fallen galls before the midges become active in the spring.

OCTOBER Checklist/Garden Tips

Control caterpillars on cool season vegetables and bedding plants with applications of Bacillus thuringiensis (or BT for short). This bacterium is deadly to caterpillars but harmless to other organisms. Control aphids with insecticidal soap or horticultural oils.

Apply pre-emergence herbicides to the lawn this month to control cool season annual weeds such as henbit, chickweed and annual blue grass. These herbicides that prevent weeds from growing must be applied before the weeds show up in the lawn.

Make compost piles from fallen leaves or use them for mulching

Purchase and plant strawberry plants this month in your vegetable gardens (or even in flowerbeds) in full sun with good drainage. Recommended cultivars are ‘Festival’, ‘Camarosa’, ‘Camino Real’ and Chandler.

Collect seeds from your warm annual flowers to plant next year. A few that have seeds relatively easy to harvest include cosmos, cleome, sunflower, abelmoschus, balsam, amaranthus, wheat celosia, mari- gold and zinnia. Do not save seed from hybrid cultivars.

October weather can be dry; water plantings as needed. Pay special attention to any newly planted areas. It is generally best to water direct seeded beds of flowers or vegetables lightly every day to make sure the seeds do not dry out. Water in newly planted bedding plants with a half strength fertilizer solution to get them off to a good start.

Make every effort to pull up or otherwise control warm season weeds going to seed now. If you let the flowers set and drop seed your problems will only be worse next year. Do not put weeds with seeds on them in your compost pile.

Fall is an excellent time to plant many herbs in the garden. A few herb plants provide a lot of harvest, so don’t plant more than you can use. Herbs to plant now include parsley, sage, thyme, dill, cilantro, rosemary, oregano, borage, fennel, nasturtium, French tarragon, chives, mint and catnip.

Your Local Extension Office is Here to Help
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For more information visit

Sarah Bertrand                                                                    Lee Rouse
Jefferson Parish Horticulture Agent                               Orleans Parish Horticulture Agent
(504) 736-6519                                                                     (504) 483-9471 

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