September Hort Tips
View the September horticulture tips provided by the Department of Horticulture and Landscape Architecture.
- Native Pecan Field Day
By Becky Carroll, Senior Extension Specialist, Fruit & Pecans
The Leon Bailey Family, Oklahoma State University Pecan Management, Okfuskee County Extension, and the Oklahoma Pecan Growers Association are hosting a Native Pecan Field Day on October 12 from 2:30 – 6:00 p.m. Check-in will begin at 2:30 pm and the meeting will be at 3 p.m.
- A few topics that may be included:
- Assessing Forested Area – Marking Pecan Trees
- Developing a Native Grove
- Equipment for Tree Cleanup
- Thinning out Remaining Pecans
- Native Pecan Inputs
- Grazing & Forage
- Prolonged Drought Stress Effects
- Wildlife Depredation
- Updates on the 2023 Season including insect & disease observations
Anyone can attend the free event, but registration is required by October 10 since dinner will be provided. Please bring a lawn chair and plan to stay for dinner in the grove at the conclusion of the field day.
- Red-shouldered Bug (Jadera haematoloma)
By Casey Hentges, Associate Extension Specialist and Bailey Singleton, Extension Assistant
As the abundance of fruit increases in the garden, often so do the insects. There is one insect that is anticipated towards the end of each summer as the native soapberry trees are loaded with ripe fruit: the red-shouldered bug. It is easy to spot their arrival because they usually come in by the hundreds.
The red-shouldered bugs can often be found on chinaberry and golden rain trees and surprisingly do very little damage to their host plants regardless of their abundance. In fact, they are mainly recognized as nuisance pests, because of their pesky nature to want to invade our structures in search of a place to overwinter. If they do get in your home and overwinter, they do not do any damage by feeding but can leave a stain if they are crushed. While they are somewhat harmless pests it can be their sheer number that really add to the creep factor and annoyance of these guys.
They typically only have two generations per year. After the adults overwinter in a protected location, they emerge in the spring as their host trees begin to bud. There they lay their eggs in late April – May. They really prefer to feed on the fruiting structures of their host trees but may also nibble on the leaves as well. After the first generation is mature, they will produce a second generation within the same year, before they begin to repeat the annual cycle of finding shelter for the winter.
Now, the red-shouldered bug as the name may imply is a ½ inch long black bug with red eyes and red shoulders. Immature nymphs typically appear more red because their black wings have not developed or can range in size.
There is also another bug that pretty much is identical to the red-shouldered bug with two major differences. The boxelder bug prefers boxelder trees and instead of just having red shoulders, it exhibits additional red markings with 3 red stripes behind the head, and red lines on the outer edges of the wings.
So, what do we do with these pests? Ultimately if it is desired to get rid of them, probably the best way would be to eliminate their host plants. Obviously, if you don’t have their preferred food, they likely won’t be hanging out around your landscape as much. However, for many that is not an option. Cutting down beautiful trees could be an unfavorable option. So one of the first things to do is to make sure to reduce as many entry points as possible in your structure – especially around door frames and window sills. For a chemical option, many home insect chemicals will work on them like Bayer Advanced Home Pest Control or Ortho Home Defense Max. A nonchemical method to remove them would simply be to use a broom or vacuum.
While red-shouldered bugs and boxelder bugs are a nuisance, just think of them as a sign that cooler weather is upon us.
Watch the Oklahoma Gardening program about red-shouldered bugs.
- Controlling Winter Annual Weeds
By David Hillock
If winter annual weeds, such as henbit and annual bluegrass, have been a problem in the past then you will 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 site/situation and labeled to control the weeds you are targeting. Be sure to read and follow the label directions for the best results and to avoid damaging any desirable plants.
Note: If you plan to seed any areas this fall do not apply a preemergence herbicide!
Tomato Ripening and Holding
By David Hillock
As we enter the shorter and cooler days of late summer and fall tomatoes that survived the summer may begin setting fruit again. Hopefully they will ripen before freezing temperatures set in, but in case we have an early freeze that threatens the plants, tomatoes can be picked before they are fully ripe and stored indoors to complete the ripening process.
The tomato is a perishable fruit. Once the ripening process begins it can’t be completely stopped. Tomatoes ripen rapidly at temperatures of 72°F, store well at 60°F, and can be held at 55°F.
The tomato ripens from the inside out. The tomato that is called vine ripe in the trade is actually picked when pink color first shows at the blossom end.
Tomatoes will turn color and ripen in light or in the dark at proper temperatures. High temperatures (above 80°F) prevent good color and flavor development and increase the chance of decay.
In the heat of July and August in Oklahoma, tomatoes left on the plant to fully ripen tend to turn red-orange in color. To get good red color development, the tomatoes must be picked when pink color first shows on the blossom end and placed in a cooler environment. In four days, at 70 to 75°F, tomatoes will develop full red color and excellent flavor. Picking tomatoes at this stage also reduces the chances for fruit cracking and garden losses due to birds, worms, sun scald, and other causes.
For the best flavor, ripe tomatoes should not be stored in the refrigerator for any length of time. Temperatures below 55°F are damaging to the fruit. You will get top flavor if tomatoes are stored in a cool place as near 60°F as possible.
- Moving Plants Indoor for Winter
By David Hillock
If you brought houseplants out into the summer sunshine, you want to start thinking about preparing them for their return journey indoors late this month. Generally, you will want to move houseplants indoors around the time that the outside temperature is about the same as the indoor temperature. This will give plants a chance to adjust to the indoor climate before you turn on the heat and avoid unnecessary cold damage to tropicals.
Moving a plant directly from its perch on the sunny patio to its winter home in the dark living room is not advisable. You will shock the plant with the drastic change in light conditions. Instead, acclimate the plant or slowly adjust it to lower light levels. Do this by moving plants to more and more heavily shaded areas over the course of a week before finally bringing it inside.
Be sure to inspect plants for insects and diseases and treat them accordingly before moving indoors. Spraying leaves and stems with a steady stream of water will help get rid of many insects. You can also wipe stems and leaves down with a soft, damp cloth. Constant drenching of the soil in the pot will also help drive out insects that have taken up residence in the soil. If the pot is small enough, you might also remove the plant from the pot to look for insects and simply remove them by hand. Plants can also be repotted to make sure there are no unwanted pests. Insecticidal soaps are safe and can be used on many houseplants. If persistent pests are suspected spray with an insecticidal soap. More than one application may be necessary. Read and follow all label directions!
- Sunflowers - Harvesting and Roasting
By David Hillock
Harvest begins in mid-September and can run into October. A check of the flower head will indicate maturity; florets in the center of the flower disk are shriveled, heads are downturned, and a lemon-yellow color is on the backside. Pull a few seeds and split them with a knife to check if seed meat has filled. Poorly filled seeds may be due to a lack of pollinating insects.
Sunflower seeds are ripe when they fall off the head or the birds start eating them. To prevent loss, cover the heads with a paper sack, cheesecloth or nylon netting once the yellow petals start turning brown. Secure the sack, cheesecloth or nylon netting with a rubber band or twist tie to prevent seeds from dropping. Heads can also be cut with about a foot of the stem attached and hung in a warm, dry, well-ventilated, rodent and insect-free place. Cut the heads once a few seeds start turning the traditional black with white stripes. The flavor will not be as good as those ripened on the plant, but less loss will occur. Once the seed is dried, it can be rubbed easily from the seed heads. Humidity levels must be kept low to prevent spoilage. Sunflower seeds will remain viable for seven years when stored in a cool dry, dark location.
Raw mature seeds may easily be prepared at home by covering unshelled seeds with salted water (2 quarts of water to ¼ to ½ cups salt). Bring to a boil and simmer two hours or soak in a salt solution overnight. Drain and dry on absorbent paper.
Put sunflower seeds in a shallow pan in a 300-degree F oven for 30 to 40 minutes or until golden brown, stirring occasionally. Take out of oven and add one teaspoon of melted butter or margarine to one cup of seeds. Stir to coat. Put on an absorbent towel. Salt to taste.
(Sources: Ohio State University Extension Factsheet, Horticulture and Crop Science, Growing Sunflowers, HYG-1228-92; Illinois Coop. Ext. Service, Horticulture Solutions Series, Sunflowers—Harvesting)
- Now is the Time to Plan for Spring Flowering Bulbs
By 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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. Though, there are a few species tulips to consider that should last for several years. 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, 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.