Western Mountains and High Plains
Remove Lawn Weeds
For a better lawn next year, remove the weeds in early fall. This is one of the best times to kill weeds since they're storing food energy for winter. Hand-pull individual weeds or use least-toxic herbicides. Read and follow label directions carefully.
Fertilize the Lawn
Autumn is one of the best times to apply the first application of fall fertilizer. Use a balanced turf food containing iron that is formulated for our region, since soils are predominantly alkaline and lack available iron. A final fertilizer application can be made in mid to late October. Aerate the lawn before applying the fertilizer to allow nutrients to filter down to the root zone and reduce soil compaction. Water the lawn thoroughly after applying the fertilizer.
Divide perennials such as daylilies, peonies, yarrows, primroses, and penstemons that have become overcrowded. Also, using a spading fork, loosen and lift clumps of irises. To create healthy divisions, use a sharp knife and cut clumps through the roots into smaller, wedge-shaped sections. Replant into soil that has been amended with homemade compost or a combination of sphagnum peat and compost. Keep well watered.
You can't beat homemade compost for enriching the soil for next spring. Add disease-free plant debris, grass clippings, hay, straw, leaves, and vegetable table scraps to the compost pile; then moisten, cover, and turn the pile regularly. If the pile is built so it heats up properly, the compost will break down in a few months. Work finished compost into the soil wherever you'll be planting spring-flowering bulbs this fall.
Pruning in late summer and fall can make plants more vulnerable to injury during an early freeze. Hard-pruning practices will also inhibit the hardening-off process and reduce the accumulation of food energy for next season's growth. Prune dead or broken branches now, but wait to do major pruning chores until late winter or early spring.