By Edward Hill, North Kildare BKA
The planting of wildflower meadows has been encouraged to increase biodiversity and improve the aesthetic amenity of an area. In most garden centres and on-line there are many Wildflower mixes available promoting their benefit of increasing pollinator numbers by providing both Pollen and nectar availability.
But how beneficial are they and what plants do they contain?
I have looked at 17 different seed mixes from 5 different suppliers to see what they contain. Altogether these mixtures contain 29 different plant families with 111 species in total.
The largest family is Asteraceae ( Comprised by plants with composite flowers like Daisies) it has highest number with 23 species included, followed by Fabeceae (Plants in the pea family Lupins, vetches) with 12 species ,Brassicaceae (Plants in the Mustard and cabbage family) with 10 species and Poaceae (Grasses) with 6 species.
Two of the Suppliers have (Poaceae) grass species in their mix, one has 2 species while 3 mixes have 5 species. One supplier lists one of its mixes using Latin names only while the other suppliers list theirs using Common Names.
The website Irish wildflowers advertise 37 different mixtures suitable for different habitats and locations. While Fruithill Farm has 3 mixtures listed. The other three suppliers I looked at were from England.
Following the launch of the All-Ireland Pollinator plan in 2015 there has been an increasing interest in the role urban environments and their habitats can play in sustaining pollinating insects.
In Ireland we have recorded 99 species of bees. There is one Species of Honey bee which is managed by beekeepers although there are some reports of feral colonies in places, there are 21 species of Bumblebees and 77 species of Solitary bee.
The plan indicates that Pollinators are under increasing pressure due to loss of habitat, Fragmentation of habitat, In breeding, Isolation, pests and diseases and the application of herbicides and pesticides. The Common Agriculture policy as implemented by the EU also has impacted on habitats, land use and biodiversity.
Some reports indicate that urban environments can support larger numbers of pollinators if forage is available while there is also some evidence that a shortage of forage sees lower numbers of pollinating insects in a habitat. The increase in the number of beekeepers and their colonies in urban areas are also suspected as contributing to the increased competition for scarce food resources available to other pollinating insects.
It is reported that the higher numbers of pollinators in a habitat relates to the variety of flower species growing and the availability of pollen and nectar to sustain them throughout their breeding season.
The widespread popularity of the All-Ireland pollinator plan and the recognition of the importance that pollinators play in the environment has raised public awareness of the impacts we have had on our local environment.
This awareness of pollinators is linked to concern with our food supply, climate change and the declining number of pollinators in the environment. Both mainstream media and social media carry lots of reports on the subject.
In order to survive and successfully raise their young, pollinators require forage from flowering plants as they have evolved to rely predominantly on both Nectar and Pollen from flowers.
It is believed that an average honey bee colony requires approx. 120 Kg of nectar and 20 Kg of pollen to sustain its colony throughout the season. While both Solitary bees and Bumblebees require less.
That requirement sees the need for a large number of flowering plants to be available throughout the breeding season, any gaps in this supply could see colonies perish due to starvation.
There are numerous private individuals, community groups, councils and state managed land planting wildflower seed mixes to encourage pollinators.
A lot of groups actively involved in planting wildflower meadow include, Tidy town associations, Newly formed biodiversity groups with an interest in pollinating insects, Beekeeping groups, County councils, private business and government organisations with rewards and recognition available for their achievements such as green flags, certificates and cups.
Many of the wildflower mixes available are of both native and introduced plants some are annuals only while some are perennials only. There are also mixtures available with both Annual and perennial seeds in them.
When planting a wildflower meadow it is important that the selected mixture contain species that are native and allow for a long growing season with lots of flowers available to provide both pollen and nectar. In some cases a change of culture in management of an area is all that may be required.
This often includes the mistaken belief of allowing the grass to grow therefore wildflowers meadows will dominate and enhance the numbers of pollinators present. In some cases the soil will be rich in nitrogen and grass species already growing will dominate and shade out any low growing native plants.
Numerous flower rich mixtures are available see eddies table for mixes. When purchasing these mixes we do not know of their value to pollinators when in flower, these mixes while flowering must provide both pollen and nectar over the spring/summer season without any gaps in flowering for pollinators to rear their young and for the species to be successful. This means that there must be some overlap in flowering periods and the planted meadow cannot be dominated by a single species.
In the early Spring especially when Bumblebee queens begin to emerge, both pollen and nectar should be available, it is not so important for honey bees as they are managed and can be supplementary fed until conditions improve.
None of the mixtures I looked at appear to provide any early flowering resources that would provide pollen or nectar to Bumblebees foraging early in the season.
A lot of the early flowering native plants are not included in the mixtures such as Wood anemones, Lesser Celendine, Dandelion, Red dead nettle, Buttercups, Speedwel, selfheal, Bugle and ground ivy which all play an important role for Bumblebee queens when they emerge in early March and are looking to establish a new nest site. Both Butterflies, Solitary bees and Hoverflies also rely on these flowering plants but have a different life cycle.
The provision of other flowering plants providing both pollen and nectar early in the season is also an important consideration when planting wildflower meadows. These should include garden plants such as Crocus, Snowdrop, Grape Hyacinths, Bluebells, lungwort, Anenomes, Flowering Current, Mahonia, Berberis Winter flowering heathers and native shrubs such as Hazel and willow.
All grasses in the mixtures are wind pollinated but there have been records of it in honey bee colonies although they are not known to forage on it.
There are a number of points worth mentioning here in relation to flowering plants.
- During cold weather flowering plants cannot produce soluble sugars as nectar to attract insects.
- Woodland flowering plants in woodland areas such as Wood Anenome, Bluebells, Lesser celendine, primroses, Snowdrops, wood sorrell and Violets must flower and set seed before the overhead canopy closes in.
- Flowering plants growing in what is now referred to as traditional hay meadows have evolved to set seed in mid summer before being cut back.
- Honey bees will feed on excess stores within the hive if necessary but will require pollen as soon as the queen starts laying.
- Solitary bees will have provisioned their nests the previous season to feed emerging larvae. But, newly emerged and mated queens will have to restart the cycle again.
- Late summer flowering plants are important to overwintering Bumblebees so that they can stock up on stores before flowers set seed.
If you plant a wildflower meadow It is important that the public understand what you are trying to achieve when managing these meadows, aside form the aesthetic value and the diversity of flowers available to pollinators, the provision of plants as a food source for caterpillars and Aphids should be considered as these are predated on by Wasps, Hoverflies, ladybirds, dragonflies and birds.
The provision of nesting sites for bumblebees and solitary bees, must also be considered as these pollinating insects often do not forage far from the colony to collect resources.
Some butterflies lay their eggs on specific plants e.g Orange tip butterflies require lady’s smock, while the rare Marsh Fritillary is dependent of devils bit scabious, and their larvae also require plants as a source of food.
Wildflower meadow plants also provide food for seed eating birds that are also attracted to them after they have set seed. The flowering period of the selected plants must extend throughout the life cycle of the pollinators colony therefore rare and introduced species will play an important role in the seed mixtures as they help extend the flowering season and fill in any gaps.
Lots of flowering plants have different flower structures for example Comfrey has a bell-shaped flower only accessible to bumblebees as they have a long proboscis.
Similarly, some plants require buzz pollination such as Borage, tomatoes, Aubergines which can only be provided by Bumblebees. Single open flowers are accessible to all pollinators and flowering plants such Fennell, Wild carrot and milfoil are easier for Hoverflies to access nectar with their mouth parts as they do not have a proboscis.
Most of the wildflower mixtures available contain a variety of flower shapes.
All planted flowering meadows should provide both pollen and nectar, especially perennial meadows which flower over a longer period rather than annual meadows which will usually all flower at the same time and for a shorter period.
When selecting plants for wildflower meadows remember that both Pollen and Nectar availability will vary throughout the season as this can be affected by soil type, water availability, topography and seed selection.
Other factors that may affect flowering include vandalism, management practices, pests and diseases, damping off and rotting of seed, weather such as frost, flooding and drought and also predation of seed by Birds, Mice, Squirrels and Rabbits.
The value of wildflower meadows in a community cannot be overlooked.
- Local groups can have an active involvement in its management which encourages ownership.
This can involve litter collection, seed collection or at a local level management such as mowing at the end of the season and removal of dominant invasive species such as thistles, nettles and grasses.
- Wildflower meadows provide opportunities for education from identification of flowering plants and visiting insects to photography and art.
- The creation of a wildflower meadow can change how a space is perceived, by bringing the countryside to an urban setting.
- Despite the wildflowers and visiting insects not everyone will be enthusiastic as green spaces with meadows can be perceived as unkempt with long grass preventing access for such pastimes as football or dog walking.
Not all wildflower mixtures are appropriate for all sites, there is not a one mixtures fits all. The location and site needs to be appropriate for wildflowers in terms of the soil’s depth, and nutrient status.
When selecting wildflowers, it is important to:
- Select native species collected and grown in Ireland.
- If the selected wildflower area already has a selection of low growing plants like, Clover, Birds foot trefoil, Medick, bedstraw, Pine apple weed and dandelions growing then all that will be required is to change its management by reducing the amounts of times it is cut or raising the blades of the mowing deck, it can also be enhanced by the addition of selected perennial plugs to prolong the flowering period.
- For the meadow to be successful you must select your seed mix that is appropriate to the site and soil conditions.
- The management of a wildflower meadow may require the use of specialist machinery that will cut the meadow allowing the seed to fall back into the soil to regrow the following year and the old grass removed later.
- Budgets and the Availability of machinery and staff and weather conditions can and will influence when the meadow can be cut.
- It is important to consider introducing species that will provide pollen and nectar early in the spring so you may have to supplement your mixture by planting trees or shrubs in the surrounding landscape.
- There is much talk about the addition of the plant yellow rattle Rhinanthus minor to wildflower meadows but it does not grow in all meadows. It is semi parasitic on grasses and does not flower until June. It is most suitable to locations where soil fertility is low and finer grass grows, dominant grasses like Rye, Cocksfoot and couch will prevent it from establishing.
- The establishment of a wildflower meadow requires a time commitment, seed can be more expensive than grass, but if you are not managing it yourself then cost will need to be factored in.
- An annual management plan will need to be established to prevent pioneer species such as grasses, brambles, dock and thistle from dominating or introducing invasive species like winter heliotrope.
- If the soil is too rich in nutrients for a wildflower meadow to establish then other options will need to be considered such as the establishment of an alternative habitat, stripping out the topsoil already there which can be very expensive or a long term planned regime of mowing and removal of cuttings to reduce the soil fertility over time.
Finally, a lot of what we see as wildflower meadows are no such thing, they are informal planting
schemes scattered with seed mixtures bought from suppliers either locally or imported and are treated as meadows, the mixtures are sown in prepared soil usually in urban locations and allowed to flower before being mown in the Autumn when machinery and time is available.
They have some benefit in creating an awareness of pollinators in the environment and bring some of the nostalgia of wildflowers meadows into urban environments, they can create corridors for transient pollinators and link different habitats and not all the flowers are suitable for the location or supply sufficient quantities of both pollen and nectar throughout the breeding season.
They are not the answer or the solution to the problem pollinating insects are facing at the moment.
But it’s a start.
By Edward Hill, North Kildare BKA