Rodd's Seeds of Wisdom Horticultural tips and tricks from Rodd Moesel

We are already a third of the way through September and we have many choices for projects we can tackle in the Oklahoma garden. For our lawns, we can apply a weed and feed combination to fertilize the lawn while we kill the winter weeds before they germinate. If you are not worried about weeds you can make your final fertilizer application of the season. If your lawn is already well fed you can apply a granular or spray weed killer (herbicide) by itself to control those winter weeds like henbit, chickweed and annual bluegrass before the seeds can sprout. This is also prime season to overseed tall fescue seed if you want a green lawn through the winter. Plant tall fescue or annual or perennial rye grass on bare soil to prevent blowing dust and erosion until you can proceed with a full landscape plan next spring or in the future. Spring flowering bulbs are arriving now at area garden centers and nurseries and although you have a couple of great months ahead for planting these bulbs you often can get the biggest and best daffodil, tulip, hyacinth and crocus bulbs by shopping early. Our spring and summer plantings are looking good and most have put on a flush of new growth and/or flowers as we have enjoyed these shorter days, cooler nights and the surprisingly cool days. Deadhead or cut off the old flowers on plants like roses, geraniums, salvia and coreopsis to keep the energy going to new flowers, not seeds, you can enjoy from now until the killing freeze. Fall is a great time to plants trees and shrubs and gives them the chance to get rooted in and established before the following hot, dry summer.

There are a number of plants that say autumn or fall to us, probably none more than hardy mums or fall chrysanthemums. Hardy mums are perennials and will come back next season, unlike the florist or potted chrysanthemums which are an annual and will freeze out with a killing freeze. Hardy mums are now available in most all of your local nurseries and garden centers with buds or flowers already visible on the plants. They are generally available in 4” pots, 6” pots, 1 gallon, 2 gallon, 3 gallon or even 5 gallon sizes, in mum pans or decorative containers. You can keep them in a decorative container on your porch or patio or plant them in your flowerbeds for fall color. They will burst into mounds of fall color over the next few weeks and will often stay colorful until a hard killing freeze shuts down their flower show for another year. Hardy mums are available in a full rainbow of colors including red, bronze, yellow, purple, pink and white and many variations of these colors. They do best planted in full sun and should be planted away from street lights and night lights if you want them to bloom naturally in future years. Night lights will not impact the hardy mums you buy this year as the buds have already been set at this time of year. Mums are very photoperiodic and bloom with short days and long nights. They are so prolific in their flowering and use so much energy that they will require more water and more food or fertilizer than most plants. If we have warm fall weather it is not unusual that they will need watering every two or three days in ground beds and may need water even more often, even daily, if grown above ground in a decorative container. There are many styles of hardy mums including pompons, cushion, spider, anemone, quill and daisy petals to provide lots of decorating or landscape options besides color selection. Few things say fall in Oklahoma like football, fairs and hardy mums. Get in on the fun and add some beautiful and charming hardy mums to your landscape to enjoy this year and for years to come.

We have been blessed with the longest stretch of “cool” weather I can ever remember in August across Oklahoma with most mornings and evenings the last couple of weeks feeling more like fall than summer. We are already seeing these cooler temperatures resulting in new growth on many of our vegetables and flowers. It is also causing a new wave of buds and flowers on many plants from rose bushes to petunias and geraniums. These ten degrees under normal temperatures also cause many of our flowers to be more intense in color producing redder reds and pinker pinks than we achieved through the hottest parts of summer when the higher night temperatures can cause many of the colors to look pale or bleached out. Now through fall is a special time in the garden to enjoy the plants you have grown since spring as they reach maximum size for the growing season and produce this extra spurt of growth and flowers over these last nine to ten weeks of this growing season.

There are many things to do in the yard as we enjoy this fall weather in August. You can complete your fall vegetable garden planting of the semi hardy or cool season root and leaf crops. You can still plant radishes, beets, leek, parsnip, carrots, lettuce, kale, spinach, Brussel sprouts, cauliflower, broccoli and Swiss chard for harvest this fall and early winter. This is the start of the season to plant cool season grasses like tall fescue and annual or perennial ryegrass seed. If you just want to cover the ground until next spring or summer because of new construction, plant annual rye grass to prevent erosion and dust and to hold the soil until you can plant your permanent warm season lawn early next growing season. If you want a green lawn this winter you can overseed your existing Bermuda grass or warm season lawn with tall fescue between now and mid October to provide a green winter lawn that will fade out in the warm weather to your main Bermuda grass or warm season lawn. Tall fescue varieties like CrossFire III, Rebel 4, Millenium, Hounddog 6, Rembrandt and many other good varieties do a nice job to green up full sun lawns through the winter and early spring before they succumb to the heat and droughts of our Oklahoma summers. Tall fescue does perform well through the summer in shady areas. The young grass seed will do best if seeded with a lawn starter type fertilizer or you can apply fertilizer soon after germination. The grass seed will usually germinate in seven to twelve days and generally requires eight to ten pounds per 1000 square feet on bare ground or four to five pounds per 1000 square feet when you overseed an existing lawn. You will need to water lightly almost daily until the seed has germinated then you should water less often but deeper.

This is also the season to apply pre-emergent weed killers or herbicides to control winter grasses and weeds in your garden and lawn. The best time to apply a pre-emergent weed killer is two to three weeks before weed seed germination and most pre-emergents will remain effective for six to sixteen weeks after application. You can apply a herbicide only or you can apply a weed and feed type product to fertilize your desired lawn and plants while killing the weed seeds as they try to germinate. You can apply most of these pre-emergents as either a granular or liquid. The most important thing to achieve good control of annual bluegrass, henbit, chickweed and the other winter weeds is proper timing and getting good coverage. Annual weeds and grasses are usually easier to control than the perennial weeds and grasses that can more easily come back from the underground roots, rhizomes or nuts.

If you are planning fall parties, family events or just time on the porch or patio there is still time to do new plantings to create a festive and fun atmosphere in your flower beds and decorative containers. Enjoy this surprisingly cooler weather. It may be a long time until we can enjoy so much comfortable time outside in August again.

We still have lots of container gardening, watering, mulching and bug fighting to do this summer but gardeners always have and need to think ahead to work with nature and the seasons. It is time to start thinking about fall gardening. It is still early for fall mums and too hot for fall pansies but now is the time to plant most fall vegetables. Oklahoma gardeners often get some of their best vegetable harvests off the fall garden. We are sowing seeds, planting and watering in the heat but the plants are maturing, flowering, pollinating and producing harvest in the cooler days and nights of autumn. To enjoy those late September, October and November harvests you have to plant now. Plant seeds of beans, beets, carrots, corn and peas to enjoy a fall harvest during the heart of the football season. Visit your local garden center and buy young plants of squash, tomatoes, peppers, cucumber and onion plants or sets. Many of the cool season brassica and leafy vegetables can be started from seeds or plants and will keep producing even past the early frosts until we get a really hard freeze. With the use of cold frames or heavier row covers some folks can produce fresh greens all winter, if we have a mild or moderate winter. These leafy greens and brassica include an ever expanding variety of spinach, kale, cabbage, broccoli, Brussel sprouts, Swiss chard, cauliflower and a smorgasboard of lettuce varieties. You can plant many of the root crops like beets, radish, leek, parsnip and carrots and most of the leafy crops all the way into October and still enjoy a harvest this year. Warm season, frost tender, crops like tomatoes, peppers, corn and cucumbers need to be planted at once in order to get a reasonable harvest before our first freeze in early November. The first hard freeze will usually kill all the warm season vegetables like tomatoes, squash, corn and peppers unless you provide extra protection for those crops. The cool season crops like kale, lettuce, peas, cabbage, carrot and cauliflower will keep growing and producing until the more brutal and extended parts of winter arrive.

Many of your existing vegetables will get a new lease on life and a “second wind” or fresh burst of energy as the night temperatures start to drop, the days get shorter and the intensity and duration of daytime heating or temperatures moderate. This summer has not been as brutal as the recent drought years and we have been blessed with some cooling and refreshing summer rains so more of our spring vegetables may have survived the summer heat and be ready for a fall rebound to add to our new fall garden plantings we make this weekend and over the next few weeks. Although we are planting for fall results, it is still summer and so we will need to water and mulch these new plantings like it is summer to help them get established and off to a good start. Even though we don’t know the date, there will be a definite end to the growing season when the hard freeze overwhelms the “anti-freeze” level of each crop. Some crops will be overcome at 32 degrees freezing, others at 25 degrees and some crops at 20 degrees or even lower. As the temperatures cool the pollen will remain viable longer on crops like tomatoes and peppers and this will greatly improve the pollination rate which helps result in more and bigger peppers and tomatoes as we move into fall and shorter days.
Vegetables are not the only plants that will get a “second wind” in the garden the next few weeks as many of our color plants like begonia, geraniums, impatiens, petunias and many others that survived the summer will produce new growth and a wave of fresh more intensely colored flowers as we cool down heading towards fall. There is so much beauty in our yards, in our parks and at our public gardens like the zoo and Myriad Gardens. Please get outside and enjoy, contemplate and celebrate the joys and wonders of nature in your own yard and across our great state.

Summer is the season when our yards and plants need our human help the most. We have expanded the planting season over the decades as we moved from just seeds, cuttings, division and bare root plants to the ready availability of container grown trees, shrubs and plants that you can plant at most any season. Although we can start and transplant our chosen plants in many ways and sizes these days they still require water, especially during these hot, dry dehydrating days of summer. Some plants can’t take the intense heat and drying winds at all without extra life giving water and will perish in the extreme heat. Others can survive without extra water but will drop leaves and show marginal leaf burn as well as wilting as they try to “right size” to the available water. Most of the state was blessed with some great rejuvenating July rains earlier this week and it is amazing how our trees and plants perk up, look greener and happier after one of these refreshing rain events. My dad used to say that most any rain in Oklahoma in July or August is a very good thing. Water from the water hose may not be as refreshing as a good rain but it still can make the difference in not only survival but the ability of your plantings to actually grow, flower, fruit and look good in spite of our heat.

In this punishing phase of summer you need to observe your plants and water as needed. Deep rooted trees, shrubs, perennials and turf are often fine with the equivalent of an inch of rain per week and count on you for that rain if it does not fall naturally from the sky. Shallower rooted annuals, new plantings, hanging baskets and container gardens may need supplemental water every other day or even daily when we flirt with triple digit temperatures and may require up to 2 to four inches of rain equivalent water spread over the week. Remember smaller, shallow containers have less soil mass and can hold less water so they will dry out more quickly and more often. Plants in the sun will dry out more quickly than plants in the shade. Plants in windy areas will dry out more quickly than plants in secluded or protected areas. Plants in lighter weight soilless mixes will dry out more quickly than plants in heavy soils or loamy soils. Plants in containers or hanging baskets will dry out more quickly than plants grown in the ground. The flowerbeds I planted and mulched only need about half the hand watering compared to the similar flowerbeds nearby I never got around to mulching with a couple inch layer of bark or hull type mulch. Not only do the mulched beds need less extra watering but they have about eighty percent less weeds to pull and the weeds we do get are much easier to pull. If you are not mulching yet, please try out this garden practice and you will be mulching in all future summers. Mulching is an Oklahoma gardener’s best friend, especially in the summer time.

The last two weeks we have attended conventions in Columbus and Cleveland, Ohio and have been overwhelmed with beautiful container gardens sporting an amazing variety of plants in both cities. Container gardening has grown every year in Oklahoma over the last decade but we are still way behind those cities where they decorate city streets, most every restaurant and many of the retailers and office buildings besides all the imaginative home and apartment decorative containers. These days you can express your inner artist or designer in the container you select to plant as well as the plants you plant in your decorative pots. Folks pot up everything from the thousands of choices in plastic containers to the beautiful Asian ceramic pottery, old shipping pallets, wheel barrows, wash tubs and other collectibles. You can still pot up great decorative containers just to decorate your home or business or to get ready for summer or fall parties and events. Remember the bigger the container, the easier it is to manage the soil moisture and the less watering is required.

We are now in the heart of Oklahoma summer weather which means bright sunshine, long days and often intense heat. From now through the end of August the most important job for Oklahoma gardeners is making sure your flowers, vegetables, trees, shrubs and lawn get adequate water. The deeper rooted your plants are the less often they will need supplemental watering as they will access to more soil moisture. Annuals and shallow rooted plants will need your watering help more often, even daily or every other day if grown in containers, hanging baskets or open well drained soils. Learn to read your plants to know how often to water based on heat, wind and soil conditions. Softer, tender plants will wilt or turn limp from drought stress. Most all plants, even deeply rooted and trees will turn a lighter shade of green, even slightly grayish or bleached out when really dry and pleading water. It is best to soak good when you do water so the moisture will soak 6” or more into the earth rather than just squirting or spraying the foliage of your plantings.

There are some plants that absolutely love the heat, the hotter the better, as long as they get sufficient rain or water to support their growth. Sweet Potato vine can grow several inches per day when we are at triple digit temperatures. Periwinkle, penta and copper leaf plants all grow and flower best when the heat seems the most challenging. One of the prettiest flowering shrubs we enjoy in Oklahoma is Crape Myrtles and they bloom and do best over the next few weeks when the heat can seem intense. Somebody needs to start a Crape Myrtle Festival or make Crape Myrtle our state flowering shrub since they add so much color to our Oklahoma summers. There are many wonderful varieties available with flower tones of pink, red, lavender and white. There are dwarf varieties that only grow 2’ or 3’ tall, varieties that make small trees of fifteen to twenty-five feet tall and many selections that fall in between at six to fifteen feet tall. Crape Myrtles suffer very few insect problems but they can suffer from powdery mildew when we get damp or high humidity conditions. Mildew can be controlled fairly easily with a good fungicide. Some varieties can suffer winter freeze back during really hard winters although most of the newer varieties have been selected for more and brighter flowers and improved winter hardiness. Hundreds of thousands of Crape Myrtles are grown every year by the large wholesale nurseries in our state to meet the increasing demand for this colorful heat loving flowering shrub. Many of the newer varieties have even been bred and developed here in Oklahoma by renowned plant breeder Dr. Carl Whitecomb who crosses and trials many acres of new Crape Myrtle every year at his Lacebark Publication farm outside Stillwater. You can plant new Crape Myrtles into your landscape even now in the middle of summer if they have been container grown so that they have a well established root system and you are prepared and committed to water them regularly the rest of this growing season until they are well rooted in their new home.

If you are growing tomato plants in a container you may want to move them to a shady or cooler area for the next six to eight weeks to keep developing new fruit. Although the tomato plant will still grow and can look reasonably well if they get enough water while above 90 degrees, the fruit stops setting on most varieties when above 90 degrees or so. They will still flower but will get much less, if any, fruit when so hot. You can improve your hot summer fruiting if you install shade cloth over your tomato plants if planted in the ground or by moving container tomatoes under the shade of a tree or building to increase summer fruiting.

Don’t forget to walk your garden to stay ahead of summer pest problems, to water your plants as needed to avoid drought stress and too mulch you’re planting to cool the soil, reduce weed competition and to conserve soil moisture while reducing the need to provide extra water to your gardens.

Rodd Moesel serves on the State Board of Oklahoma Farm Bureau and was recently inducted into the Oklahoma Agriculture Hall of Fame. Email garden and landscape questions to rmoesel@americanplant.com.