September Gardening Topics
2020
- Twig Girdlers - Casey Hentges, Oklahoma Gardening Host
Have you been raking more twigs than leaves lately? If you are concerned because your tree seems to be shedding its branches, don’t be too alarmed by this late season “pruning” there is a simple answer.
There is an insect called a twig girdler that is more noticeable this time of year. The twig girdler, appropriately named, chews completely around the bark of small twigs leaving the twig attached to the tree only by a small column of wood in the center. As the wind picks up in the fall, these twigs are snapped off and fall to the ground leaving small branches that often look like they have been through a pencil sharpener.
As the adults twig girdlers emerge in late August to early October, they feed on tender bark near the end of the branch and then mate before girdling twigs and laying eggs. The eggs are inserted beneath the bark or slightly into the wood, usually near a bud scar or adjacent to a side shoot.
What makes this insect smart and the reason they chew a collar around the twigs is because the larvae are unable to survive in living twigs. By chewing the cambium layer around the twig they have girdled the end of the branch which will result in it dying.
Smaller twigs from ¼ to ½ inch in diameter are most commonly girdled. Eggs are laid during or after the cutting process. The number of eggs per twig normally ranges from 3 to 8 but may range up to 40. Each female deposits 50 to 200 eggs which hatch in about 3 weeks, resulting in potentially a numerous amount of twigs falling from a tree.
The small larvae, which are a whitish, cylindrical, legless grubs that reach about ¾ inch in length at maturity, overwinter in the dead twig either in the tree or on the ground. The larvae grow rapidly in the spring and tunnel toward the severed end of the twig, feeding only on the woody portion and leaving the bark intact. The mature larva closes off the tunnel with shredded fibers to form a pupation chamber.
After a 12-14 day pupation in August and September, the adult chews a circular hole in the bark to emerge, living 6 to 10 weeks to repeat the cycle. This lifecycle results in one generation per year.
The adults are longhorned beetles that range from ½ to 5/8 inch long. They are grayish brown in color with a broad, ashy-gray band across the middle of the wing covers. The antennae are at least as long as the body.
Twig girdlers are commonly found on pecan, hickory, persimmon, and elm. They also attach to oaks, honey locust, hackberry, poplar, dogwood, sourwood, and various fruit trees.
It is not uncommon to see the ground under infested trees almost covered with twigs that have been cut off. Mainly this simply affects the aesthetic quality of ornamental plantings causing the development of many offshoots that adversely affect the symmetry of the tree. However, infested pecan trees can result in low nut yields.
The best practice to prevent these insects from returning is good sanitation. By raking and destroying infested twigs and branches beginning in fall and early spring you are removing many of the next generation from your landscape.
Oklahoma Gardening Video - https://youtu.be/uUGA3aMZoF4
- A Second Crop - David Hillock. Consumer Horticulturist
Remember there are several cool-season vegetables that can still be planted throughout the month of September for a fall/winter crop of fresh produce. Plant veggies that grow rapidly, such as lettuce, spinach, mustard, radish, beet, collard, Swiss chard, turnip, kohlrabi, and kale. Onion, garlic, and leek are also planted now, but won’t be ready to harvest until late spring to early June of next year. If you can get broccoli and cauliflower seedlings, plant those as well.
The key to survival for these cool-season plants is to keep the plants cool and moist until temperatures begin to drop. You can purchase shade cloth specifically for this purpose, or use other materials found around the house. Old window screens, scrap wood staked vertically, extra pieces of landscape fabric etc. work well in reducing temperatures and dry winds that can exhaust young plants. Grass clippings sprinkled lightly on top of young seedlings about 1/8-inch thick, cools the soil, reduces evaporation, and suppress weed seeds on the soil surface.
- Controlling Winter Annual Weeds - David Hillock, Consumer Horticulturist
If winter annual weeds, such as henbit and annual bluegrass, have been a problem in the past then you will for sure want to apply a preemergence herbicide as soon as possible. Many of our winter annual weeds germinate in the fall or early winter and survive as very young plants until late winter or early spring when conditions are more favorable for growth. Waiting until you notice them is too late.
The key to effective control is timing. Preemergence herbicides must be applied well in advance of the expected germination time of the weeds to be controlled, for winter annual weeds this is by September 15. In addition, the products must be watered in to activate them. At least ½ inch of water either through rainfall or irrigation if no precipitation is expected within a couple days after application is recommended. In some cases the product needs to be incorporated into the upper surface of soil.
There are several products available in the garden centers that will effectively control germination of most winter annual weeds. Some are labeled just for turf areas and some are labeled for both turf and ornamental areas. Examples of products labeled for use in lawn and ornamental areas include some containing benefin + oryzalin or those containing bensulide. Another product available that contains trifluralin can be used in ornamental and vegetable beds. Again there are several to choose from; choose one that is labeled for your particular site/situation and labeled to control the weeds you are targeting. Be sure to read and follow the label directions for best results and to avoid damaging any desirable plants.
- Garden Preparations for Winter - Lynn Brandenberger, Horticultural Food Crops
As we enter the fall gardening season you may want to consider what your plans are for your fall and winter garden. Your plans may include a fall/winter garden or possibly you are tired and ready to give it a rest at this point in the season. If you are considering not gardening this fall then consider this: Now is an excellent time to add organic matter to your garden’s soil and to plant a winter cover crop.
Being good stewards of our garden soil is a critical part of gardening. If you’ve been thinking about adding manure to build soil structure etc. fall is a great time to do it since you have 5-6 months before things kick-off for your spring garden. Why is that important? Well. . . the food safety experts point out that we need anywhere from 90 to 120 days between adding manure and harvesting fresh produce for salads etc. So with 5-6 months available that gets us to 150 to 180 days from application until planting, much less harvest. That is plenty of time for mother-nature to take care of any pathogenic critters that could cause food safety issues.
If you are going to add manure or old hay etc. you really need to ask some questions about how the feed that the animal ate or the hay was grown. The real issue is herbicide carryover which is a nice way of saying that even after the hay has passed through the digestive system of the animal it will still contain herbicide residues that could potentially be a disaster for our garden or field. Below is a table listing herbicides that could be a problem. Long story short, ask questions it could save you a lot of grief.
Herbicides that contain picloram, cloypralid, aminopyralid, Sulfonyl ureas:
Pasture and agronomic
Curtail (2,4-D and clopyralid)
Cimarron Max (metsulfuron, dicamba and 2,4-D)
Dicamba DMA Salt (dicamba)
Forefront (aminopyralid + 2,4-D)
Grazon Next (aminopyralid + 2,4-D)
Grazon P+D (picloram +2,4-D)
Milestone (aminopyralid)
Redeem R&P (triclopyr+clopyralid)
Surmount (picloram+fluroxypyr)
Turf and Lawns
Confront (triclopyyr+clopyralid)
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Dicamba DMA Salt (dicamba)
Lontrel (clopyralid)
Millennium Ultra Plus (2,4-D+clopyralid+dicamba)
Millennium Ultra and Ultra 2 (2,4-D+clopyralid+dicamba)
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Fruit and Vegetables
Clopyr AG (clopyralid)
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Stinger (clopyralid)
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There may be other herbicides, but the main point is to know what has been applied and what may cause carryover problems. Source of information was NC State university Cooperative Extension.
Next on your list of things to do would be to plant a winter cover crop. There are some great cover crop mixes out there, so that’s one possibility. Another is to blend your own mix for use in your field or garden. It is a good idea to include both a winter tolerant cereal grass like wheat or rye along with a legume. The grass will help to build up organic matter in the soil and the legume will provide your spring crops with nitrogen. Legumes that are inoculated can fix 50-100 lbs. of nitrogen per acre which is like getting free nitrogen fertilizer and as an extra bonus it’s organic!
We have done cover crop research and I personally like to use winter wheat combined with crimson clover, possibly lespedeza and maybe even throw in some tillage radish to break-up hard areas in the sub-soil. The other great thing about cover crops is that they will help prevent soil erosion, latch onto leftover plant nutrients that may be left from this year’s crops and they also shade the soil and prevent weed seedlings from getting control of the site. So there are some great reasons for planting a winter cover crop.
In conclusion, even if you are determined to continue gardening through the winter consider adding manure and a good cover crop mix to areas of the field or garden that will not be cropped. With a little extra time and effort there are some great benefits to be gained.
- Now is the Time to Plan for Spring Flowering Bulbs - David Hillock
It won’t be long and you will be receiving catalogs in the mail, emails from bulb suppliers or see spring flowering bulbs show up in the garden centers. Why? Because fall is the best time to plant them. In Oklahoma late-September through mid-November is the ideal time to start planting depending on where you live in the state.
To get the best quality bulbs, order early or visit your garden center soon for the best pickings. The larger bulb usually means a healthy, vigorous plant. I enjoy browsing through the selections available from the many bulb suppliers because they have a larger variety of cultivars and species to choose from and I get to dream of cooler weather and bright colors in my garden. After months of a drabby winter, there's nothing like an explosion of color to let you know that spring really is finally here.
For best results follow these do and don’t tips.
1) DO plant generously. It is better to plant tulip bulbs in groups of 20 or more, spaced about a foot apart, than to place them in tight clumps or scatter them all over an area. You'll get more bang for your buck. Daffodils provide a fantastic display when organized in swaths, sort of like a lazy river.
2) DO plan for a longer display of blooms by mixing different species and varieties of species. For example, there are early, mid, and late season blooming varieties of tulips. By choosing some of each you can extend the blooming time over several weeks.
3) DO choose a site with excellent drainage. Bulbs hate soggy conditions, which can be common in Oklahoma clay soils. Plant in raised beds, on slopes, or any other well-drained spot. They also need full sun, at least 6 hours of direct, unfiltered light a day.
4) DON’T plant too deep, not even tulips. Plant bulbs no deeper than about two to three times the diameter of the bulb. For example, if a bulb is 1 inch in diameter, plant about 2 to 3 inches deep.
5) DON'T plant in straight rows. This looks stiff like tin soldiers standing in a row, and that lovely massed effect of the bulbs is lost.
6) DON'T expect tulips and hyacinths to last for years and years. Most of the tulip varieties succumb to Oklahoma summers and heavy clay soils. Treat them like an annual and expect to replant again next fall. Daffodils, crocuses, grape hyacinths, and others, on the other hand, tend to naturalize or multiply year after year. Old clumps that seem to be declining should be divided! Keep the largest, healthiest bulbs and discard any small, weak, or damaged bulbs.
Be sure to also try some of the other spring-flowering species besides the typical ones, such as:
Alstroemeria ligtu (Peruvian lily), Allium spp. (Giant allium), Anemone coronaria (Poppy anemone), Anemone nemorosa (Wood anemone), Convallaria majalis (Lily-of-the-Valley), Crocus spp. (Crocus), Fritillaria imperialis (Crown imperial), Fritillaria melagris (Checkered lily), Galanthus spp. (Snowdrop), Muscari spp. (Grape hyacinth), Scilla campanulata, also Hyacinthoides hispanica (Wood hyacinth or squill), and Scilla spp. (Squill).
In addition to spring-flowering bulbs, don’t forget that pansies can be planted now along with ornamental cabbage and kale, and other cool-season flowers. The pansies will be quite happy through most of the winter and come spring, by the time the bulbs are popping through the ground, they will begin to delight you with a colorful display.
- Tips for Bringing Plants Indoors - David Hillock
Because of our warm humid weather during summer, many indoor, tropical plants are often grown outdoors. They love the hot, humid conditions of our summers and will often grow leaps and bounds. However, cooler weather will soon be arriving and these tropical plants will need to be moved indoors.
Now is the time to begin acclimating plants. Do not move plants immediately from outside to inside. Plant stress may occur when plants are exposed to sudden changes in temperature, light and humidity.
Light levels inside the home are much lower compared to the bright sunlight outside. To help your plants adjust to the lower light levels before moving them inside, gradually reduce the light levels to which they are exposed by placing them in shaded areas for a few weeks. Then move the plants indoors for 1 to 2 days a week. Gradually leave plants indoors longer. This will allow the plants to acclimate to the new environmental conditions.
Frequently check plants for insects while moving them from locations. You do not want to infest healthy plants with insects. Remove infested and dead plant material. If insects are seen, treat them with a labeled insecticide outdoors.
- Patio is Center of Outdoor Entertainment - David Hillock
A popular trend in landscaping and gardening is to spend more time enjoying the outdoors even if it is in your own backyard. This has been especially important recently during the pandemic and being stuck at home. Creating a backyard oasis or even a simple outdoor room can enhance the overall enjoyment of your home. One of the easiest places to start in most yards is the back patio (or deck). The patio becomes an extension of your indoor living space and is often a central gathering place and as we slowly come out of quarantine we can enjoy it even more with family and friends. You can’t have a party without a party room, and to your landscape, that “room” is the patio. Here are some tips to ensure the most successful patio possible:
- It must be convenient, that is, accessible. Hopefully it will be adjacent to the kitchen, den or dining room, a short step from your home.
- It should seem like the intermediary, the space between your indoor living area and the great outdoors. Folks’ eyes should be guided across it, out into the yard, to a focal point toward the back of the landscape.
- It should be adequately sized. Figure 100 to 200 square feet per family member. If your current patio doesn’t have that much space, expand it. You can use pavers or flagstones or concrete squares placed against one or more edges of the existing concrete patio. Or, cover it completely as you also enlarge it by using concrete pavers or epoxy-stone surfacing.
- Shade it from the hot sun. If it’s to be used primarily in the evening, plant a small shade tree a few feet away from the west edge of the patio. If it will primarily be a breakfast nook, let the shade be to the east.
- You may prefer a permanent arbor. If so, build it with sturdy timbers. Use beams that are large enough to shade it well, but open enough to permit free flow of the air. Use deciduous vines to provide shade in the summer, and then allow winter’s rays to reach the patio surface below.
- Select quality patio furniture. First and foremost, it needs to be comfortable. It should be made to last with minimal repainting. Sit in the furniture for a while before you buy it, just to be sure it’s comfortable for long stretches.
- Use striking annual flowers and tropical plants to give the patio a festive appearance. Choose handsome terra cotta patio pots, also quality hanging baskets and then fill them with showy plants.
- Finish it off with quality night-lighting. Down-lighting is the most natural, giving the illusion of moonlight. Lights give your special patio an entirely different feeling at night. It’s like having two gardens for little more than the cost of one.
- Pecan Topics Zoom Meeting on September 11, 2020 - Becky Carroll, Associate Extension
Specialist, Fruit and Pecans
September Topics for Pecans zoom meeting is scheduled for September 11 at 1 p.m. Items to be discussed include wildlife depredation and control; getting the orchard floor ready for harvest; equipment maintenance before harvest; stink bug and leaf footed bug control; and crop updates.
Participants should register at https://dasnr.zoom.us/meeting/register/tJUlf--hqT8pG9PheHJcGvx4ebhKy_TAQ9-Q to receive a link to join. Extension educators can receive in-service credit. Please share with interested clients. Recording will be available at later date.
- Pecan Field Day, September 19, 2020 - Becky Carroll
The Oklahoma Pecan Growers Association (OPGA) is hosting a Fall Field Day on September 19 from 1 ‑ 4 p.m. The Saturday event will be located at Selman Farms, 571 East 156 St. North, Skiatook, OK 74070. The field day is free of charge but participants should email ssloan@okpecangrowers.com to register.
Agenda items include: OPGA announcements and special business meeting; harvest equipment maintenance and tips; tree thinning; wildlife depredation and control demonstrations; pecan weevil monitoring and control; sprayer demonstrations; crop outlook and progress; and orchard's history.
The OPGA is taking necessary measures to keep attendees and guests healthy. They will not be using trailers for tours. Please bring a lawn chair, maintain social distancing (Keep one cow of space between you and others) and bring a mask if preferred.