There are many different kinds of bees that act as pollinators, including honey bees and bumblebees which are social bees living in colonies. Other kinds are solitary bees such as leaf-cutter bees, mason and mining bees, and there are other pollinators including hoverflies. Growing herbal medicines provides a great opportunity to support bees and other pollinators. Ideal for bees are smaller plants including herbs with single (not double) flowers such as in the mint (lemon balm, marjoram, mint, rosemary, sage), carrot (fennel, wild carrot), borage (borage, comfrey, lungwort), rose (rose, meadowsweet, strawberry), daisy (coneflower, marigold, yarrow) and mallow families. Many other plants are useful, such as ivy which flowers in the autumn when relatively few other flowers are to be found.

But what about the many other medicinal woody plants available, including trees and shrubs? It turns out that bees actively prefer foraging on trees, even when they are few and far between. Donkersley (2019) has argued strongly for a more three-dimensional approach in designs with trees and hedgerows to support insects that rely on pollen and nectar. It seems that trees provide greater levels of protein than grasslands, and bees will seek them out when foraging. Rather than a single layer of herbs, trees and shrubs provide a three-dimensional storehouse right up into the sky! From April to June this is an important source, accounting for the main supplies of nectar. These woody habitats provide more efficient resources for pollinators due to ‘absolute resource density’ (Donkersley, 2019, p.81). They also provide shelter, nesting and an overwinter habitat, which means they should be part of more effective conservation strategies for pollinators. 

Pollination is a very important component in lots of agricultural systems. But many practices in agriculture are contributing to the decline of wild insect pollinators, especially the use of pesticides. This is yet another reason why we should all support organic growing methods. A timely research study by Varah and colleagues (2020) has been published which shows how agroforestry could provide another way to combat a decline in pollinators. The study shows that plots linked with trees can outperform monoculture plots on a number of counts. In this UK study by researchers at the University of Reading and the Organic Research Centre, a direct comparison was made between matched plots on organic farms. Three main measures were used, the numbers of bees, the range of insect pollinator species found, and the effect on seed production. Where there were agroforestry components, there were twice as many hoverflies and solitary bees. The study demonstrated that species richness was increased up to 10-fold and seed setting was up to 4.5 times greater where plots were linked with agroforestry. As the researchers say, this is robust evidence that agroforestry ‘can support greater numbers of wild insect pollinators, greater pollination service, and … species richness’ (Varah et al., 2020, p.10). 

Pollinating apple

But when I looked up favourite trees for bees online I found that relatively few trees and shrubs with medicinal uses were included. So, in addition to the list of herbs above, here is my starter list of trees and shrubs that are both good for insect pollinators and could be ued by us in herbal medicine. They are roughly grouped from spring through to summer.

February: alder, oregon grape, willow; 

March: blackthorn, cherry plum;

April: bird cherry, crab apple, rosemary, sweet gum, sweet bay; 

May: barberry, broom, cramp bark, hawthorn, horsechestnut, raspberry, rowan, sweet chestnut, walnut;

June: alder buckthorn, blueberry, elder, dog rose, lavender, lime, sage;

July: buddleia, myrtle; 

If we want to support bees and other pollinators then we really should include more of these woody plants, and all benefit to us if they are also medicinal! Quite a few of these healing plants are detailed in The Medicinal Forest Garden Handbook if you want to find more information about growing and using them.

Bee on Oregon grape

REFERENCES
Donkersley P (2019) Trees for bees. Agriculture, Ecosystems & Environment 270-271: 79-83.

Stobart A (2020) The Medicinal Forest Garden Handbook. East Meon, Hampshire: Permanent Publications.

Varah A, Jones H, Smith J, et al. (2020) Temperate agroforestry systems provide greater pollination service than monoculture. Agriculture, Ecosystems & Environment 301: 107031. https://doi.org/10.1016/j.agee.2020.107031

Photos by Kay Piercy copyright 2020, kay@studio4art.co.uk