All in all, we have had a decent summer with reasonable temperatures and adequate rainfall. I think the marker for the summer of 2021 can go to the weeds! So, as you address some fall weeding chores you may also want to do a little preening to give some of your annuals and perennials a facelift for fall.
As we descend into fall annuals and perennials will rebound but first, we need to get rid of the old, ragged growth. Several gardeners have told me they have given up on the season and thrown out their annual containers. I understand the urge but if you dead-head spent blooms and cut back annuals they will put on new, lush growth. A dose of water-soluble fertilizer will help with growth, color and additional bloom set. In a matter of a couple of weeks it will look like you have a whole new set of containers to enjoy.
Herbaceous perennials will also respond to some late summer pruning. Leave those in full-bloom, like golden rod, aster, mum and helianthus; but go ahead and clean up the perennials that have finished blooming or those inclined to repeat bloom throughout the season. I regularly clean up perennial geraniums, salvias, eryngiums, gaillardia and others so they continue to bloom all summer. Others simply benefit from having diseased or damaged foliage removed for aesthetics in the garden.
Take note that I am referring to annuals and perennials in the garden and not woody shrubs and trees. I do not recommend any clean-up of woodies (unless the wood is dead) at this point, it is too early in the autumn season to attend to these matters. Instead, we should wait to do any of these chores until after several hard frosts and dormancy has occurred. Pruning woodies too early in the fall may result in new growth that will be killed by frost. The traditional hedging shrubs like Taxus, boxwood and hollies should be left alone for now, as well. Wait until several hard frosts occur then you can shape them up for winter.
The rush to mulch is usually something we think about in the spring of the year but consider tackling this chore now. A 2-inch layer of mulch, if it is not already there, will help cut down on weeds and moderate soil moisture. Be sure not to pile mulch too high or around the base of the plant’s stem or trunk. We don’t want to rot a root crown or in the case of woody plants or trees we always want to see the natural flare of the trunk. We do not want to see what looks like a telephone pole sticking out of the ground.
Remove the suckers from the base and branches of sucker prone trees. Suckers will compete for resources from the parent tree and if these trees are under stress, we certainly don’t want to add insult to injury. Suckers are unsightly but they are also competition. Crabapples are most notable in this regard!
And, finally, get those summer weeds under control. Controlling weeds now and preventing flowering and seed production will go far in overall weed management. Prevent late summer seeding and you prevent next year’s annual weed crop. If nothing else, dead-head anything about to set seed; pull the easy stuff after a rain; and use spot treatments of a total kill herbicide to kill your hard to control perennial weeds like poke and dandelion if you must. Many late summer perennial weeds are most effectively controlled during their fall growth cycle because they are trying to store energy before winter. This means they will take in the herbicide more efficiently. For continued control you can use corn gluten pre-emergent products to safely prevent weed seed from germinating. The corn gluten products also provide small amounts of nitrogen which will benefit the desirable plants in the garden.