Whether we know it or not, we've declared war on our native bees. Habitat destruction, overdevelopment, and shrinking plant diversity all impact native bee populations. At a time when honeybees are disappearing, we need our native pollinators more than ever.
If you're a gardener or homeowner, you can make a difference. Here are 12 things you can do to help native bees thrive.
1. Cut back on the mulch.
Gardeners love mulch, and it does have its benefits. But look at the mulch from a bee's perspective. Ground-nesting bees dig nests in the soil, and a layer of mulch will discourage them from taking up residence in your yard. Leave a few sunny areas free of mulch for the bees.
2. Minimize your use of weed barriers.
Ditto on the weed barriers. If you don't like to weed, barriers of black plastic or landscape fabric may be an easy solution for keeping the garden weed free. But bees can't tear through these barriers to reach the soil surface, so rethink your weeding strategy. If you must use a barrier, try laying down newspapers instead – they'll biodegrade over time.
3. Plant a variety of flowers that bloom from early spring to late fall.
Don't expect native bees to wait around until your vegetable crops bloom. Bees need pollen and nectar to live, and if they can't find flowers in your yard, they'll move elsewhere. Digger bees begin foraging as soon as spring arrives, while bumblebees and dwarf carpenter bees are still active in the fall. Plant a variety of flowers to provide blooms from early spring to late fall, and you'll keep native bees happy all year.
4. Leave some sunny areas of your yard free of vegetation.
Many native bees nest in the ground; these bees usually seek out loose, sandy soils free of vegetation. Leave a few patches of ground so they can burrow, and they won't have to travel so far to pollinate your flowers. Remember, bees like it sunny, so try to designate plant-free areas where there's enough sun exposure to please them.
5. Provide some wood for carpenter bees.
Carpenter bees look for soft wood, such as pine or fir, in which to make their homes. While you might consider them pests when they burrow into your deck or porch, they rarely do any structural damage. Carpenter bees don't feed on wood (they feed on nectar and pollen!), but do excavate nests in lumber. Let them be, and they'll pay you back by pollinating your fruits and veggies.
6. Plant pithy vines or canes for dwarf carpenter bees.
Dwarf carpenter bees, which grow to just 8 mm, spend their winters nestled inside hollowed out canes or vines. Come spring, the females expand their pithy burrows and lay eggs. Besides providing these native bees with homes, you're providing food; dwarf carpenter bees love to forage on raspberries and other cane plants.
7. Limit pesticide use.
This much should be obvious, right? Chemical pesticides, particularly broad spectrum pesticides, can negatively impact native bee populations. Use pesticides conservatively, or better yet, not at all. By doing so, you'll also encourage beneficial predators to stick around and feed on your insect pests.
8. Leave some leaf litter in your yard.
Digger bees burrow in the ground, but they don't like their homes exposed. They prefer to make their nests in places with a little leaf litter to camouflage the entrance. Put down that rake and leave a few areas of your yard the way Mother Nature intended it.
9. Don't mow your lawn so often.
Bees like to hang out in your lawn, especially when on warm, sunny afternoons. Many "weeds" provide good sources of nectar and pollen, so bumblebees and other native bees may be foraging underfoot. Mowing kills bees, and trims the flowers that feed them. Try to let your lawn grow a little longer before you mow. When you do need to trim the lawn, do it during the cooler parts of the day or when it's cloudy to avoid killing foraging bees.
10. Provide a source of mud for mason bees.
Mason bees are known for their skilled nest construction. They look for existing holes in wood, then carry mud to the site to craft their nests. If you've got some exposed soil in your yard, keep it moist for these native bees. You can also provide a shallow dish of mud to encourage mason bees to make their home in your yard.
11. Leave some weeds for the bees, and limit your herbicide use.
Pollen bees don't discriminate between your prized perennials and the weeds in your lawn. Weeds are wildflowers! Bumblebees love clover, so don't be so quick to break out the weed killer when clover invades your lawn. The greater the diversity of flowering plants in your yard, the more native bees you'll attract to pollinate your plants.
12. Install some artificial nests for mason and leafcutter bees.
Both mason bees and leafcutter bees make tube-shaped burrows, in which they lay their eggs. These bees don't usually excavate their own burrows, preferring to find existing cavities and build within them. Fill a coffee can with a bundle of drinking straws, mount it to a fence post in a protected area, and you've got yourself an artificial nest for these efficient pollinators. If you're handy, drill some holes in a block of pine or fir wood instead.