Wild flowers (and other wild species) are sown for three main reasons. The first is to achieve a purely Economic Objective which gives priority either to the establishment costs or the costs of long term maintenance. The Aesthetic Objective. aims to establish vegetation which is pleasant to look at. Finally, an Ecological Objective aims to achieve benefits which are not solely human-related.

These objectives are not mutually exclusive, and with effective planning and careful species selection they can be combined to achieve a vegetation cover which is cheap to maintain, pleasant to look at and affords a valuable habitat for wildlife. Thus a mixture of slow growing grasses and wildflowers established on a motorway verge can provide a succession of wild flowers throughout the summer and support butterflies and ground nesting birds, while having minimal maintenance requirements.

When the costs of establishment are considered in isolation, the cheapest form of acceptable vegetation cover is pure grass. The reason is that commercial grass seed is very cheap in comparison to most wildflower seed (£5/kg. for grass, £100/kg. for many wildflower species). However, most areas of pure grass look unsightly unless mown several times per year, thus annual maintenance costs are high. Pure grass is boring to look at and of low wildlife value. By including selected low-cost wildflowers, a much more valuable cover can be established at little additional cost. This additional cost of seed will be recovered by the reduced mowing costs after the vegetation is established, a reduction of mowing intensity being made acceptable by the succession of flowers blooming throughout the summer.

A simple approach is to sow a standard mixture of 80% slow growing grasses and 20% wildflower species selected for a wide tolerance of habitats and ready public appreciation of their flowers. This type of mixture requires no more soil preparation than grass, can establish effectively on all except extreme soil types, will produce a succession of flowers throughout the summer and can have low maintenance costs. A range of mixtures appropriate to most economic and aesthetic objectives is included in the Wildflower Mixtures Pricelist on the Herbiseed web site (www.herbiseed.com).

If there is a requirement to establish a vegetation cover rapidly for erosion control or client satisfaction, a fast germinating annual grass can be sown at 10-20kg. per hectare in addition to this mixture. This grass is intended to cover the soil for the first few months, then die out, leaving space for the slower growing grasses and wildflowers. Herbiseed recommends annual foxtail, Alopecurus myosuroides for this purpose. It is less competetive and less likely to persist into the second year than the annual ryegrass, Lolium multiflorum or L. westerwoldicum usually recommended for this purpose.

Since many biennial and perennial wildflowers do not flower until the second year after sowing, it can be advantageous to add up to 10kg. per hectare of annual wildflowers to the perennial mixture. These species such as poppy, cornflower and corncockle will flower in the first summer but seldom persist into subsequent years.

The standard mixture may be made more appropriate to a particular purpose by adding species selected from the lists of species in the following section.

Establishing vegetation to achieve ecological objectives requires a precise definition of the objectives for the project and careful selection of species to meet these objectives. Factors to consider are:

The objectives of the project, both wildlife related and human related.

Constraints; ecological, cost, time, future management.

Soil type.

‘Natural’ flora in the vicinity.

The likely trend of ecological succession on the site.

The future management of the area.

In most situations, grasses will be sown together with other wild plants to provide a naturalistic cover at a time when the wildflowers are not actively growing. Often a mixture of 20% wildflower seed and 80% grasses is used, but this can be varied according to the project requirements. The standard grass mixture often used is 10% Agrostis capillaris, 25% Festuca rubra, 40% Cynosurus cristatus,

A selected standard mixture from the Herbiseed pricelist may be appropriate for some ecological objectives, or can form a base to which selected species are added. Alternatively, the ecologist can specify a mixture specifically for the site and have it formulated by Herbiseed. In this case it is advisable to discuss the price and availability of the species with Herbiseed before finalising the composition of the mixture.

The following lists of species characteristic of certain habitats have been selected for their suitability for establishment from seed.

Explanation:

* = tolerates the soil type

** = grows well on the soil type

*** = characteristic of the soil type

In most situations where wildflowers are specified for aesthetic objectives, consideration needs to be given to the desired height of the vegetation, the way in which it is to be managed (e.g. frequency of mowing), and selecting a mix of species to achieve a succession of flowers throughout the growing season. The interest of the area can be extended into the winter by including species with persistent seed heads (teasle, tansy,) and interesting fruits such as bryony. This is relatively simple with wildflower meadows, but in dense woodland habitats most species tend to flower early. Selecting later flowering and climbing species for the woodland margins and open glades can help extend the visual interest of these areas.

A number of wildflower species establish reliably in many situations, these species tend to be relatively cheap (>£100/kg.) and are used in several standard wildflower mixtures. Other species may be less readily available, more expensive as seed, and less predictable in their establishment. Herbiseed welcomes enquiries from ecologists and site managers about the cost, availability and suitability of particular species, and will willingly discuss the options available for achieving the desired visual or ecological effect in wildflower establishment on a particular project.

Click here to open a discussion with Herbiseed Technical co-ordinator.