Summertime gardening challenges in Oklahoma

Here we are at the halfway point of 2008, a good time for a little reflection and looking ahead as we pause from our normal daily activities to celebrate the birth of our great country tomorrow. In Oklahoma we usually end up with a 6 ½ or 7 month growing season depending on when we get our last killing freeze in late March or April and our first killing freeze at the end of October or in November so that means we are about 3/7 or a little less than halfway through our growing season. You can still plant annuals and container gardens to get 4 months of enjoyment this year. You can still plant perennials, trees and shrubs to enjoy for a lifetime.

We have been blessed with relatively moderate weather this season and nice, fairly well spaced rainfall except for our friends in the Panhandle and far Northwest Oklahoma who are struggling with very dry, almost dust bowl, conditions. We are entering the couple of months that are usually our hottest and driest of the year when your flowers, trees, shrubs, vegetables and lawn depend on you for some extra water to avoid stress and leaf drop. Celebrate when we are fortunate enough to get natural rainfall. Nothing matches the cleansing renewal powers of rain but when your plants get dry on these long hot summer days be prepared to water them either by hand with a waterhose, with hose fed sprinklers, an automatic sprinkler system or best of all with a slow, deep penetrating drip watering system. Water is most effective when applied as a soaking rain, watering more deeply to pull the roots deeper in the soil rather than sprayed or squirted everyday where the water stays near the surface and tends to cause shallower root systems making your plants more vulnerable to heat and cold damage. You will treat your plants better if you soak them once a week or as needed depending on heat stress, type of soil, type of plant and container size rather than a quick spray down every night. Applying a good top cover mulch of some type of bark fiber or chips or natural hulls will keep the soil cooler, reduce weed problems and most importantly stretch our valuable water resources by reducing surface evaporation. Mulching often cuts watering needs in half.

Besides watering one of the other challenges of Oklahoma gardening in the summertime is battling worms, spidermites, bagworms, scale and other bugs. Most of these types of pests are temperature responsive and they produce many more eggs per batch and much more often in hot weather and that is why they seem to explode in population as we get hot. We can go from very low bug pressure where we don’t mind sharing a little bounty with the rest of nature to such severe pressure it really effects the health of our plants in very short order.  I have been getting many calls about different worms on vegetables and lots of e-mails about bagworms that have just had a population explosion and are threatening many of our junipers and even some trees. It is always a good idea to take a sample of the problem to the garden center for diagnosis and prescription. Many of these worm problems can be controlled by picking them off but make sure to put them in a bag and throw them in the trash or they will often just climb back on the plant. For more severe problems spray with carbaryl (often sold as Sevin or Eight) or you can use BT (bacillus thuringiensis) an organic microbial spray that is very effective on all types of worms, particularly when small. Spinosad, another biological control that was discovered as a byproduct of rum distilling is also very effective on worms including bagworms.

Scale continue to assault some of our shrubs, particularly some types of euonymus which are too accommodating as hosts. Scale are best controlled with an a ultrafine or superfine, highly processed oil spray that smothers the scale or you could use Malathion.

Spider mites are really exploding in population with the warmer weather and we have a limited number of consumer options since so many retail chemicals have been pulled from the market especially for edible vegetables and fruits. On edible or ornamental crops you can use a biological spray containing Spinosad or natural oils like extract of neem seed or a product like Mite-X with a combination of   cottonseed oil, clove oil and garlic extract to suffocate the mites. You can use Malathion, permethrin or deltamethrin on ornamentals like marigolds. Always read and follow the label directions and it is usually best to spray early in the morning or late in the day when the temperature is a little cooler.

Enjoy some family time this weekend as we celebrate the birth of our country, the wisdom and courage of our forefathers as they founded our country and lets all recommit to do our part to maintain our freedoms for our children and our neighbors. Remember a little time in the garden is relaxing, good exercise and helps put everything in perspective.


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