Wild purple asters line roadsides and ditches across rural America. These hardy perennials bloom profusely in late summer or early fall creating a stunning display of color that ranges from white to shades of pink and purple. Cultivated varieties exhibit similar blooming patterns making them ideal for adding color and dimension to fall gardens. Tolerant of both poor soil and drought, asters are relatively carefree, other than routine care for both the plant and the soil, and thrive in USDA Plant Hardiness Zones 4 -8.
Browse nurseries and greenhouses to select the appropriate aster for your garden. Traditional purple asters are always a good choice, but there are many sizes, shapes and colors available in cultivated asters.
Select a location that receives full sun for the majority of the day. Six to 8 hours of direct sun is preferred.Till the soil to a depth of 8 inches. Remove rocks, roots and clods of soil and rake smooth.
Prepare the soil by amending with organic matter. Layer 2 to 3 inches of compost, peat moss or well-rotted manure and work into the soil with a spade or garden tiller. Organic matter improves soil texture, promotes drainage and supplies nutrients to growing plants.
Plant purple aster seedlings to the original growing depth, spaced 18 inches apart. Group in clusters of three or five to create the illusion of plants springing from nature.Consider multicolored groups or select several shades of purple asters to create an eye-catching blanket of color.
Water thoroughly to moisten the soil to the root level and keep soil moist until new growth appears.Once established, asters tolerate dry soil, but seedlings require adequate moisture to develop strong root systems.
Pinch or trim back asters 7 to 14 days after transplanting, leaving three internodes (the area on the stem between leaf nodes where new leaves appear) on the main stem. Repeat every two to three weeks until late July. This forces the plant to develop multiple branches to support an abundance of blooms.
Apply water-soluble fertilizer designed for flowering plants every 2 to 3 weeks.. Cease fertilizing plants when the first buds being to open. Fertilizer at this time inhibits blooming time.
Deadhead purple aster blooms by clipping or snapping off old blooms as soon as they begin to fade. Deadheading tricks the plant into thinking it has not produced enough blooms to set seed and reproduce. When deadheaded promptly, asters continue to send out new blooms.
Water deeply to moisten the soil to the root level once a week. This encourages deep root formation. Purple asters may require more frequent watering in periods of excessive drought but typically tolerate dry spells well.