Transition season provides beauty and garden cleanup time
By Mary Fran McClure
WSU Chelan/Douglas County Master Gardener
Looking out our kitchen window in late September, we notice a few branches of our weeping crabapple transitioning from green to yellow. Cooler weather and longer nights are signaling the tree to head into dormancy.
Chlorophyll that makes those leaves green is being transported down to the roots this time of year. It’s an efficient way to save valuable nutrients for next year’s growth cycle and enables deciduous plants to better survive a cold winter. A plus for us is enjoying those glorious fall colors.
Yes, there’s a definite bite in the air, fall flowers such as asters are in their glory, and we gardeners feel the push to get many clean-up chores accomplished before cold weather sets in. Projects done now can show huge benefits next growing season.
September has been the month to lessen watering and help direct those plants headed into dormancy.
Sunflowers have been dominating our garden, enhanced by a myriad of goldfinches flitting about hunting seeds of sunflowers as well as echinacea, rudbeckia and other seed-producing perennials. I will cut withering daylilies, annuals and other plants first, leaving the others for a while, alas, for the birds.
Later this month, I will clip off seeds from annual marigolds. They add stunning summer color to raised beds, but they’re goners once cool temperatures set in. The dried seeds stay viable in an open box in the garage, ready for planting next year around the same time as tomatoes and other warm-weather vegetables and flowers. All need warm soil temperatures.
It’s time to pull up those annuals and divide perennials that have grown profusely. They’ll bloom better than those left in large clumps competing for nutrients, sun and water.
“After the first frost, mow your lawn one last time to one and a half to two inches,” says Martha Bean, Master Gardener intern who helped research my column of putting the garden to bed.
She adds, “As the moist air returns to our region, fall is an ideal time to plant new shrubs and perennials, to set our spring bulbs, and do blanket seeding of native grasses and wildflowers.”
October is the time to dig and save cannas if you’re so inclined. Once their leaves start to turn yellow, cut them off, dig the rhizomes and divide them. I use a root saw and hori hori knife to make the division easier. Toss the old blackened rhizomes and save the new little sprouts and younger rhizomes. I group them in a large container, surrounded in reused well-draining soil. They’ll do well stored a garage or other cool location that doesn’t freeze.
Cannas survive just fine as long as you don’t feel sorry for them and overwater. A small amount about once a month seems sufficient to keep them alive without becoming soggy and rotting. Plant them out once we’re back into warm weather, as they won’t take off until it’s feeling like summer.
After harvesting and removing end-of-the-season plants in your herb and vegetable garden, add compost or plant a cover crop such as crimson clover or fava beans to help rejuvenate beds for next year. If you’re doing any legume cover crops such as the two mentioned, be sure to buy a package of inoculant at the same time, as it enhances plant growth.
Clean tools, store containers that may break when frozen, and in general get ready to spend more time indoors.
All in all, this transition period can be immensely productive while still enjoying the glories of fall’s beautiful colors.