Horticulture Tips for July

Home Grown  by Keith Reed
Consider the following tips for your July landscape:
  • High temperatures combined with high humidity signal high fungal disease pressure. Fungicides, the products used to combat these diseases, work better as protectants than they do as curatives. In other words, if you have a plant that’s badly diseased, simply treating with a fungicide may help slow the problem, but it may not cure it.
  • Many blooming perennials are now passed peak and can benefit from a good dead-heading. In some cases, yarrow being a good example, a hard pruning will make way for the plant to rebloom nicely later this summer. Not all perennials will respond in this way. If you unsure, contact us in the Extension office.
  • Perennials like iris and daylilies can be divided and/or moved the later part of the month. This is also a relatively good time to do the same with peonies. I say relatively because peonies prefer to be left alone and should only be divided if they are really overgrown.
  • Now is the time to get serious if you are considering a fall vegetable garden. OSU Fact Sheet #6009 Fall Gardening (PDF / Mobile) provides helpful information on this under-utilized possibility for gardeners in our part of the country. Growers using minimal materials and supplies as temporary covers are reporting extending the fall growing season by an average of 30 days. The same principles are also allowing gardeners to start their spring gardeners well in advance of our normal spring planting dates.
  • One of the biggest issues fall gardeners face is high soil temperatures for tender plants. Make sure your plans include some type of shade cloth or screen (and mulch) to help keep soil temperatures in check for the first few weeks of a fall garden.
  • As summer advances and the rains diminish, look for potential water leaks or inconsistencies in your irrigation patterns and correct as needed. Also remember to shut the system down for a few days when we get those bonus summer rains.
  • If you have not already done so, adjust the mowing height of your cool season turfgrass (such as tall fescue) upwards. About 3” will help it hang on through the summer heat. Yellow or brown areas may very well indicate brown patch disease which will be made worse with excessive water. Check the soil moisture before assuming it needs more water. Do not fertilizer it until this fall.
  • Manage your bermudagrass lawn growth with fertilizer management. Let grass clipping volume help you determine nitrogen needs. If you are mowing weekly and excess clippings are building up, consider reducing your fertilizer rates.

For more information on this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at
keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

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