Kim Sullivan, Anoka County Extension Master Gardener
These days the news is all abuzz with bee-friendly lawns. As of August 15th, our low-maintenance fall lawn care season begins. It’s easy to care for your lawns and bees at the same time. Bee lawns require less mowing, fertilizing and watering, too.
Grass and broadleaf weed roots grow longer as the days cool in order to store more food for the spring. For grass, that means fertilizing with 2/3 of your annual nitrogen application right around Labor Day. Fertilizing also keeps the grass thicker to shade weeds and discourages low-fertility weeds like black medic. For broadleaf weeds, from September through mid-October is also the best time to treat them if you need to use chemicals. As weed roots extend, they get solid doses of weed killer and you’ll see impressive results in the spring.
Spot treat your weeds; don’t use hose-end sprayers. There are several chemical options available; select one that is labeled for use on your weed. If you have a choice, Triclopyr has shown less damage to neighboring plants than combinations which include Dicamba and 2,4-D. Read and follow the label directions when you use chemicals.
What’s bee-friendly about that? Leave your clover patches (dandelions and creeping charlie, if you can stand them) alone!
While we’re talking chemicals, let’s touch on Japanese beetles. They are a pest of lawns and will emerge about mid-July. They feed and lay eggs in the soil until September. If you have problems with grubs eating the roots of your grass, it’s best to deal with that now.
But do you need to treat? Dig a triangular cut into your lawn and lift the grass. Did the patch lift easily? Can you see at least 10 grubs per square foot under the patch you dug? If not – don’t treat! Japanese beetles can fly five miles to feed. The guys bugging you aren’t from your ‘hood.
If you treat for grubs, the chemical will likely also kill bees. So if you have clover and other bee-friendly flowers in your yard, mow it before you treat so the food source for bees is removed. Watch your watering as well; a low-maintenance, deficit watered lawn is less likely to attract the beetles than a wet one.
Dethatching, aerating and seeding between August 15th and the middle of September is best now for any lawn. If you’re adding bee flowers to the existing lawn, closer to the middle of September, scalp the lawn to one inch high, aerate, then add seed. Using low-maintenance fine fescue seed blends works especially well with lawn flowers like clover, self-heal (prunella vulgaris ssp. lanceolata), ground plum and creeping thyme.
Mow high. Bee lawn flowers are selected for their ability to bloom at much shorter heights than they might normally. Leave as much height as you can, at least 3 ½ inches before you mow, taking no more than a third of the grass blade at a time when you do.
For more information on bee friendly lawns, go to https://www.beelab.umn.edu.