Why Plant for Bees?
There's lots of talk about the need to plant trees for bees, but what does this mean and why should we do it.
Providing sources of Pollen & Nectar
Planting for bees means supplementing the existing ecosystem with Pollen and Nectar sources through the seasons. Bees operate to a pollen calendar. To bees, spring starts with the first rush of pollen producing flowers, which may actually be in the late winter. Bees produce a brood rearing pheromone which tells the hive to start getting ready to grow in the spring or to naturally collapse the hive down as they enter winter. This regulates the bee colony size to the supply of food available.
As the first pollen resources arrive in the late winter, the hive will start working, cleaning out old cells in the hive ready for new pollen and nectar. Every frame of bees they create will consume a frame of honey and a significant amount of pollen. Depending on what is available in the environment, bees will feed new larvae (bees that haven't hatched yet) a mixture of older stores and new collections. Problems can occur when there are only a few flowering species that produce for a short period and then the supply of pollen and or nectar stops. This plus a patch of cold weather can be fatal to hives that have started to build up rapidly in the spring and then hit a wall where they will potentially starve. In these conditions hives will stop producing bees and potentially cannibalise brood. The result being that as the older bees die out, the bee population will crash at a later point. The impact on honey yields for these hives can be dramatic as often these conditions occur in the October dearth period where the bees that should be being produced by the hive will be the first population that hits the initial honey flows of November and December.
Modern beekeeping tries to supplement the bees diet with sucrose and vegetable protein to compensate for this. It can be successful but the wide variation in environmental factors makes supplementary feeding an expensive exercise with more bees being put into more marginal environments and also high densities of hives causing overpopulation. Bees need a number of lipids, amino acids and minerals, some of which is not normally supplemented. Correct feeding also requires a long term awareness of the local ecosystem and weather patterns to properly understand where the bees are on the pollen and nectar calendar.
Poor pollen and nectar supplies in Autumn can result in a brood break where the hive instructs the Queen to stop producing bees due to insufficient stores. The resulting impact is fewer young winter bees to keep the colony strong over winter and a crash in the population coming through the July and August period. A stronger hive through winter ensures there is sufficient bees to create heat to keep the colony warm and healthy. Hive health through winter is also impacted by the amount of lipids and amino acids the bees have collected and stored in their body along with the presence of varroa and other diseases. Bees benefit from a wide range of forage as do most animals.
Within the New Zealand ecosystem, honey bees are an introduced insect and as such, the native flora has not adapted to the needs of the honey bee. This is evident by the lack of native pollen and nectar producing trees through the late summer, autumn and winter. Most native trees flower during August to January.
Identifying flowering periods for your project
To plant for bees requires an audit of what is available in the area and also identifying any strategic objectives in the planting plan. An example of a key objective could include reducing the options of flowering sources for bees when specific targets such as Manuka are flowering. The overall concept is demonstrated in the diagram below. Other considerations include the variable flowering window for some species and also that some species produce on a biannual basis or flower irregularly.
Of course, there are many other planting options other than what is shown above. The above is a generic view of the main hero plants that produce for bees in most places. Generally in planting for bees we would look for trees that produce regular flowering within a seasonal window, and if the tree does produce pollen, we would target trees that produce high protein pollen as opposed to low grade pollen. Pollen quality varies widely between flowers, from none at all, to poor to very high quality. Bees will actively target flowers with over 20% protein in their pollen and these plants should be a priority in any planting strategy.
Planting trees for bees can be incorporated into most urban and rural planting. It could be a new hedge row to provide wind protection, a riparian strip to protect waterways or forestry blocks for timber or firewood. There are many amenity trees that are exceptional for bees and can be incorporated into shade trees or laneway plantings.
How TreesforBees Plant Nursery can help
Here at the TreesforBees Plant Nursery we specialise in growing trees identified from the research of the Trees for Bees not for profit organisation and published in their Trees for Bees Planting Guides. We are also working to increase the range of lesser known trees that are good for bees but are not typically commercially available.
We can help with advice, farm planting plans and costings so let us know about your project.