As cooler weather moves into Colorado, October is the perfect month to accomplish gardening projects. KUNC's Gardener Tom Throgmorton has a few suggestions on way to take full advantage of October and these autumn days.
Most perennials can be cut back in the fall. It’s depends more on the energy level of the gardener than on the plant. Some folks are burnt-out on gardening this time of year. So save the pruning for spring.
Some perennials are better left uncut. Ornamental grasses, Coneflower, Black-Eyed-Susan, and asters have seed heads with winter interest or winter bird food. Don’t cut them back until late winter or spring. We leave our sunflowers up until the birds have eaten all the seed.
Cut back flowering shrubs after they’ve bloomed. Autumn is a good time to prune the flowers off of Blue Mist Spirea, Russian sage and summer blooming Spirea. In the spring trim out any winter die back. Don’t prune spring blooming shrubs like Spirea or lilacs.
Once we’ve had a few hard frosts and the plants are dormant they can be moved. Fall is a great time to move that shrub that’s gotten too big or perennials that need more room. Take as much soil as possible with the roots. A three foot plant should have at least a foot diameter rootball. Prune transplants back a third to halfway. Water the plants into their new garden home.
Pine trees are losing their inner needles. This is a natural process. Older needles turn brown and drop during fall and winter winds. Trees look rough with bunches of brown interior needles. Austrian and Ponderosa pine lose three year old needles. By next spring they will only be holding this year’s and last year’s needles. Bristlecone pine holds onto five years of needles.
Big, old pine and spruce need extra water going into our driest season, winter. Soak the entire root zone. The roots on a forty foot tall spruce grow more than forty feet in diameter around the tree. The rule of thumb is ten gallons of water for every inch of trunk diameter. A six inch diameter trunk needs sixty gallons of water.
If these old trees are stressed they become vulnerable to insect pests. Ips beetles attack spruce. Zimmerman moths are killing the tops and large branches of pine. Both insects attack weak trees. Keep big trees well watered and in good health to protect them from insects.
Plant garlic and spring flowering bulbs. Plant each clove of garlic about three or four inches deep in the veggie garden. Cluster groups of bulbs together for a blast of color in the spring.
