Monthly Horticulture Tips 

Oklahoma Cooperative Extension Service
Division of Agricultural Sciences and Natural Resources
Oklahoma State University

Garden Tips for AUGUST

By David Hillock

Download the entire list here.


  • August is a good month to start your fall vegetable garden. Bush beans, cucumbers, and summer squash can be replanted for another crop. Beets, broccoli, carrots, potatoes, lettuce, and other cool-season crops can also be planted at this time. (HLA-6009)
  • Soak vegetable seed overnight prior to planting. Once planted, cover them with compost to avoid soil crusting. Mulch to keep planting bed moist and provide shade during initial establishment. Monitor and control insect pests that prevent a good start of plants in your fall garden.

Fruit and Nut

  • Continue protective insect applications on the fruit orchard. A good spray schedule is often abandoned too early. Follow directions on last application prior to harvest. (EPP-7319)

Lawn and Turf

  • Grassy winter weeds like Poa annua, better known as annual bluegrass, can be prevented with a preemergence herbicide application in late August. Water in the product after application. (HLA-6420)
  • Areas of turf with large brown spots should be checked for high numbers of grubs. Mid-to-late August is the best time to control heavy white grub infestations in the lawn. Apply appropriate insecticide if white grubs are a problem. Water product into soil. (EPP-7306)
  • Tall fescue should be mowed at 3 inches during the hot summer and up to 3½ inches if it grows under heavier shade. (HLA-6420)
  • For areas being converted to tall fescue this fall, begin spraying out bermudagrass with a product containing glyphosate in early August. (HLA-6419)
  • Irrigated warm-season lawns can be fertilized once again; apply 0.5 lb N/1,000 sq ft in early to mid-August.
  • Brown patch of cool-season grasses can be a problem. (HLA-6420)


  • Towards the end of the month, divide and replant spring-blooming perennials like iris, peonies, and daylilies if needed.

Trees and Shrubs

  • Discontinue deadheading roses by mid-August to help initiate winter hardiness.
  • Watch for second generation of fall webworm in late August/early September. Remove webs that enclose branches and destroy; or spray with good penetration with an appropriate insecticide.


  • Water compost during extremely dry periods so that it remains active. Turn the pile to generate heat throughout for proper sterilization.
  • Always follow directions on both synthetic and natural pesticide products.
  • Watch for high populations of caterpillars, aphids, spider mites, thrips, scales and other insects on plant material in the garden and landscape and treat as needed. (EPP-7306)
  • Water all plants thoroughly unless rainfall has been adequate. It is better to water more in depth, less often and early in the morning.


Staking Trees

Fall is a great time to plant trees. One task that should be considered when planting new trees is support. Staking newly planted trees can be beneficial in providing support to the trees until they develop strong enough root systems to stand on their own. However, not all new trees need to be staked. If it is a small tree and in an area protected from high winds then it probably does not need to be staked. If it is a larger tree and/or one with dense foliage that may catch the wind or is planted in a windswept area then it might be a good idea to stake the tree.

The material used to attach the tree to the stake should be broad, smooth and somewhat elastic. Do not stake the tree too rigidly. Always allow for sway. Too tight or prolonged staking results in an overall weaker tree and is more subject to girdling of the trunk. Triple staking provides more protection against strong winds and lawn mowers. Support stakes and guy wires generally should be removed after one growing season. If staking material is left in place for more than two years the tree’s ability to stand alone may be reduced, and the chances of girdling injury are increased.

So, the best thing to do is assess the situation and stake only when necessary and briefly.  Prolonged staking can have a detrimental effect on the development of the tree. Too often, staking materials end up injuring or girdling the tree because they are left on longer than necessary. 


Urban Friendly Trees

Many of our urban and suburban landscapes don’t leave us a lot of room for large shade trees. And unfortunately, some of the most commonly sold trees are those that grow very large and fast, which makes them too big for the typical landscape, and because they are fast growers, often weaker. 

For example, I live in a neighborhood that was established in the mid-1980s. The developers wanted fast growing shade trees so they planted species such as silver maple, cottonwood, sycamore and Bradford pears (half of the pears in the neighborhood have now fallen apart); all great trees, but they belong in a park setting or a large estate. Our properties are hardly bigger than the houses themselves. Large trees like those mentioned have aggressive roots, are weak wooded, and can be quite messy. When we bought our house we had a cottonwood growing about two feet from the water meter and only about 6 feet from the house – that was the first thing to come down!

So what types of trees might be better suited for a smaller residential neighborhood?  How about some small to medium-sized trees?  In addition, many of the species listed below have columnar or narrow-growing forms available. There are many species that have wonderful ornamental characteristics and still provide shade and privacy. Here are a few to consider:

Small Trees (10-25 ft tall)

  • Amur Maple (Acer tataricum spp. ginnala)
  • Buckeye (Aesculus spp.)
  • Chastetree (Vitex negundo)
  • Fringetree (Chionanthus cultivars)
  • Crapemyrtle (Lagerstroemia indica)
  • Deciduous Holly (Ilex decidua)
  • Desertwillow (Chilopsis linearis)
  • Flowering Dogwood (Cornus florida)
  • Hawthorn (Crataegus spp.) 
  • Indian Cherry (Rhamnus caroliniana)
  • Japanese Maple (Acer palmatum)
  • Oklahoma Redbud (Cercis canadensis ssp. texensis ‘Oklahoma’)
  • ‘Prairifire’ Crabapple (Malus ‘Prairfire’)
  • Rose-of-Sharon (Hibiscus syriacus)
  • Saucer Magnolia (Magnolia x soulangiana)
  • Serviceberry (Amelanchier spp.)
  • Shantung Maple (Acer truncatum)
  • Star Magnolia (Magnolia stellata)
  • Witchhazel (Hamamelis spp.)
  • Yaupon Holly (Ilex vomitoria)


Medium Trees (25-40 ft tall)

  • American Hornbeam (Carpinus caroliniana)
  • Cedar Elm (Ulmus crassifolia)
  • Chinese Pistache (Pistacia chinensis)
  • Chinkapin Oak (Quercus muehlenbergii)
  • Escarpment Live Oak (Quercus fusiformis)
  • European Hornbeam (Carpinus betulus)
  • Goldenraintree (Koelreuteria paniculata)
  • Hedge Maple (Acer campestre)
  • Ironwood (Ostrya virginiana)
  • Japanese Pagoda tree (Sophora japonica)
  • Japanese Zelkova (Zelkova species and cultivars)
  • Washington Hawthorn (Crataegus phaenopyrum)
  • Western Soapberry (Sapindus drummondii)

Download the entire list of August tips here.