September Horticulture Management
Managing horticultural landscapes in September is essential to healthy production during the growing season. Below are a few recommendations for Chouteau county gardeners.
• The average first frost is September 15 (Carter), September 18 (Kenilworth and Highwood), September 20 (Big Sandy), September 25 (Fort Benton) and September 28 (Geraldine). All fruit and vegetables should be harvested before temperatures drop below 40° to 50°F.
• Ripen tomatoes in a paper bag along with an apple, or hang the entire plant upside down in the garage.
• Plant spring-flowering bulbs.
• Transplant daylilies. Daylilies should be divided every two to three years.
• Divide and transplant clumps of peonies. When transplanting, buds should be no deeper than 1-2 inches below the soil surface.
• Cut peony foliage to the ground after a hard frost.
• Give hedges a final trimming.
• Work at least 2 inches of organic matter into the garden.
• Water evergreens 1 inch per week after the leaves on deciduous trees drop. Be sure to water evergreens until the ground is frozen.
• Seed or sod new lawns from August 15- September 15. Annual weeds do not have time to produce seed, and the grass has the entire fall and early spring to become established before the heat and stress of summer.
• Spray lawn weeds. The fall is the best time to spray lawn weeds because they are beginning to put reserves down into the root system in preparation for winter. The herbicide travels more deeply into the root system, and can kill the plant more effectively. Banvel and 2-4-D works ok on most weeds, but applying Glyphosate (Roundup) with a small paint brush is the most effective procedure on tough to kill weeds like Canada thistle, creeping bellflower and dandelion.
• Fertilize lawn close to Labor Day with one pound of actual nitrogen per 1000 square feet. Since 20-5-5 is 20% actual nitrogen, the gardener will need to apply almost 5 pounds of nitrogen per 1000 square feet (1 pound of nitrogen ÷ .20).
• Lower mower height to 1.5 inches to help reduce snow mold.
• Be sure the area around newly planted trees is free of standing water. Drain the area if necessary before winter.
Information for this article came from the MSU Extension Montana gardener’s book of days and the MSU Extension Montana Master Gardener Handbook which are both available for purchase from the MSU Extension Chouteau County Office.
