Now is the time to prepare your landscape for winter dormancy
Published: Saturday, September 14, 2013 at 6:01 a.m.
Last Modified: Thursday, September 12, 2013 at 9:12 a.m.
As the official close of summer arrives next week, it won't be long until the days become noticeably shorter. The welcome cooler weather also is a signal that the sun is continuing its relentless march beyond the equator, and for landscapers, is a reminder that a few weeks remain in which to prepare landscapes and turfgrass for winter dormancy.
Traditionally, for North Central Florida, Sept. 30 is considered the last date to prune and apply fertilizers prior to the advent of cold weather. Pruning results in the onset of new growth, which is very tender; pruning after Sept. 30 can cause damage to new growth if temperatures drop suddenly and severely, which occasionally occurs in November. Fertilizer, too, initiates tender new growth, but more importantly, fertilizer should be applied when plants are actively uptaking nitrogen — not the case when plants are in dormancy.
Nitrogen is very soluble and any that is not taken into the plant will be leached into the water table.
When considering any fertilizer program for landscape plants, one should always begin with a soil test prior to a fertilizer application. The University of Florida soil testing lab offers this service at a very reasonable price, and test kits are available at Extension Offices. Testing results may take as long as two weeks, so testing should be done immediately to get results prior to the Sept. 30 deadline. In general, established landscape plants often do not need any additional nitrogen. However, symptoms of nitrogen deficiency may be observed in leaves that are off color, a condition that can be verified with testing.
For turfgrass, standard recommendations based on University of Florida IFAS research should be employed. This means three pounds of controlled-release nitrogen per 1,000 square feet per year for St. Augustine and Zoysia grasses and two pounds of controlled nitrogen per 1,000 square feet per year for bahia and centipede cultivars. If the final nitrogen application has not been made, the deadline is approaching.
In addition to nitrogen, an equal amount of potassium should be added during the fall fertilizer application. Potassium contributes to the general health of plants and often is compared to the multi-purpose vitamin many adults take each day. For plants, potassium enhances root growth, resulting in greater drought and cold tolerance.
The end of the month also represents a last opportunity to prune hedges and other landscape plants that need an occasional trim. The cooler weather and shorter days will slow growth, and this final pruning of the season should last until the middle of next March. Shrub pruning is done to thin plant growth to facilitate air movement, or it may be needed to control the size of plants. Sometimes severe pruning is a method for rejuvenating plants, but this is a strategy more suited to spring when plants can recover immediately, rather than going through a dormant period. Remember that some plants like azaleas or camellias have already set buds for next year, so avoid pruning these — their time for pruning is immediately following bloom. Crepe myrtles are another plant that should not be pruned in fall; wait until mid to late February for pruning these.
October and November are among the drier months of the year, and some supplemental irrigation will be required to maintain plant health as plants move into dormancy. Gardeners will need to monitor landscape and turf regularly and apply irrigation when plants initially begin to show signs of stress (onset of wilt in leaves due to dry conditions). Because supplemental irrigation has not been needed since last spring, it is important to examine the irrigation system prior to its use. Check for leaks and clogged or damaged spray heads, adjust spray patterns so that they arrive on the targeted plants and not on sidewalks or paved surfaces, check to ensure coverage is uniform.
Plant management often is about limiting stress factors to ensure plant health. Applying the proper amounts of water and fertilizer and pruning at the right time are key elements in making sure plants are ready to perform when warm temperatures arrive next spring.
David Holmes is Marion County extension director. Contact him at email@example.com.