Gardening for bees

Everyone knows that the European honeybee has taken terrible hits in recent years. What is less well known is that the 400+ species of native bees in Virginia are under serious threat from the actions of human beings. Not only are native bees important pollinators of many food crops, they play an essential role in our ecosystem as a whole. Bees and a whole array of less noticeable animals -  including many species of flies, ants and beetles - pollinate the majority of the plants we see around us. In other words, they ensure the survival of most of the plant kingdom.

Click on the photos below (roughly in order of bloom time) to find plants that feed specialist bees - ones that require certain native plant species to survive.
If you feed the specialist bees, you will also be feeding the generalist bees.

Want to save the bees? This task is far more complicated than you might guess. Here is the bottom line:

1. Humans cannot reproduce the vast and complicated biodiversity of natural areas, so the first priority has to be preservation of those areas and removal of invasives. Even small patches of invasive plant species have cascading effects on the insect population of a much greater area around them. Removing those invasive plants does wonders for biodiversity.

2. Where natural biodiversity has already been destroyed, humans can help by planting a wide variety of native species. You can’t prevent species extinctions by focusing on a single plant-pollinator interaction. You have to focus on the ecosystem as a whole. So add as many species of native plants as your growing conditions allow, and cram in as many plants as you can afford. Plan for a succession of blooms from early spring to late fall.

About 80% of bees are plant generalists - they can forage on a wide variety of flowers. To support these bees, provide a succession of blooms from early spring to late fall. Use locally native plants that fit into the ecosystem.

 

About 20% of bee species are specialists, requiring certain plant species for their nectar and pollen. (An easy example is the Southeastern Blueberry Bee.) The life cycle of these bees is timed to the bloom time of their plants. One major determinant of which flowers they use is the shape of the bloom. For example, some bees have absurdly long tongues, others have short ones. All these bees (and their associated plants) are essential for a healthy ecosystem.These species are in decline and need our help the most. They are more susceptible to the effects of insecticides. 

  • Nectar: Adult bees use nectar for their own energy, and some bees are plant generalists. Many are specialists, though, requiring flowers of different shapes depending on the length of the bee’s tongue and other foraging factors.

  • Pollen: Not all pollen is the same. Bees get themselves covered with pollen accidentally and therefore help with pollination. But to feed their young, they need the pollen from specific plant species and seek it out deliberately, often “buzzing” the flowers to collect it. The population of many species of bees is limited by the availability of the right pollen. For those who have a lot of room, one strategy to provide needed food pollen from spring to late summer would be to plant native willows, native St. John’s Wort, Virginia Rose and Carolina Rose.

 

The problem with non-native plants:

Even a small patch of non-native flowers may seriously distort the diversity of bee species in your garden. It is always best to stick to natives. Seeing a large number of bumblebee individuals in your yard does not necessarily mean you have created a healthy ecosystem. If you are trying to prevent the decline of threatened bee species, what counts is how many different bee species you are seeing.

 

The problem with insecticides:

Studies of the effect of pesticides on bees have focused on short term effects on those species that have immediate economic importance to human beings, namely the European honeybee and to a much lesser extent, the Common Eastern Bumblebee. Massive and heart-breaking die-offs of declining species of native bees is largely ignored, though studies have demonstrated that they are more susceptible to lower doses of insecticides.

Nest sites
 

Most native bees are ground nesters. Provide them with some bare ground to tunnel into.

 

Some bees nest in dead plant stalks. Leave the plants in place over the winter, then cut them back to around 18 inches in late winter or early spring. At that point, the bees may burrow into the cut ends to lay their eggs. Continue to leave these stems in place until a year later, after the next generation of bees has had a chance to emerge in the early spring. By that time, those stalks will have fallen over and be laying on the ground, where they can just stay. If for some reason you need to move them, just move them gently to some out of the way place.

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Providing nest sites: Learn more.

 

Bee boxes are cute. They may or may not be helpful to bees. Learn more.

 

How to ID bumblebees and study them in your own yard: Click here

 

Fascinating lecture on plant-pollinator interactions: Click here. 

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Native species which are particularly popular with honeybees include:

Perennials​

  • Blazing Star (Liatris species)

  • Mountain Mint (Pycnanthemum species)

  • Joe Pye Weed (Eutrochium species)

  • New England Aster (Symphyotrichum novae-angliae)

  • Goldenrods (Solidago species)

Trees and shrubs

  • Tulip Poplar (Liriodendron tulipifera)

  • Maples (Acer rubrum)

  • Oaks (Quercus alba, bicolor, coccinea, falcata, marilandica, michauxii, montana, muehlenbergii, palustris, phellos, rubra, stellata, velutina)

  • Hazelnut (Cornus americana, cornuta)

  • Redbud (Cercis canadensis)

  • Dogwoods (Cornus alternifolia,amomum, florida, racemosa)

  • Birch (Betula nigra)

  • Magnolias (Magnolia virginiana)

  • Sumacs (Rhus aromatica, copallinum, glabra)

  • Black Locust (Robinia pseudoacacia)

  • Buttonbush (Cephalanthus occidentalis)

  • Summersweet (Clethra alnifolia)

  • Witch Hazel (Hamamelis virginiana)