September in the Rockies
What to do in your Mountain garden in September
Perk up container plantings with frost-resistant osteospermum. For added protection, cover them when temperatures are forecast to be below 30°.
Sow spinach for fall and early spring crops. ‘Bloomsdale Long Standing’ is one of the hardiest. Other varieties good for fall planting are ‘Avon’, ‘Indian Summer’, ‘Melody’, ‘Razzle Dazzle’, and ‘Tyee’. To protect seedlings from hard frosts, spread straw loosely over the beds.
For easy-care color next spring, plant bulbs of Siberian squill. These cheerful little flowers grow in sun or shade and will multiply into large colonies after a few years.
Add perennials with foliage that changes color in autumn. The best include sunshine yellow Amsonia hubrichtii, brilliant gold and butterfly weed (Asclepias tuberosa), and fiery red Euphorbia dulcis ‘Chameleon’.
For a blaze of scarlet in autumn, plant native, drought tolerant skunkbush sumac (Rhus triloba), a shrub reaching 2 to 5 feet tall with edible fruit.
Plant crabapples for fruit suited to delicious jams and jellies. For large fruit, plant Dolgo or Brandywine.
To prevent slipping, clean up and compost fallen fruit from driveways and sidewalks.
Bring in houseplants before the first frost. First rinse off foliage and submerge the pot into a bucket of water for a few minutes to dislodge any hitchhiking pests.
Check vegetable beds daily to harvest summer squash while small and most tasty.
Stop fertilizing and watering potatoes to get them ready for harvest. Dig tubers after the tops die down but before hard frost damages the potatoes.
To overwinter coleus, fuschias, geraniums, plectranthus, sweet potato vines, trandescantia, and many other types of tender perennials, take cuttings. Cut stem tips 4 to 6 inches long and trim off lower leaves with scissors. Stick cut stems into moist potting soil and cover with a plastic bag until roots form. Many of these also root well in water in a colored glass container.