Pictorial Planting - Streets, Parks, Squares & Meanwhile Spaces

Creating a vibrant, colourful and memorable public realm

The vision for Ebbsfleet Garden City is for colourful vibrant and memorable planting to permeate all areas of the public realm.

We look at four methods of planting on the following pages which create a colourful, loose textured, naturalistic look. They share roots in natural plant communities, such as meadows, prairies, woodland ground flora. They are designed for low maintenance and so are suitable for extensive areas, such as

• Street verges,

• Parks, squares, and

• Meanwhile spaces.

1. Pictorial meadows

The Pictorial planting approach was pioneered by Nigel Dunnett at Sheffield University. Nigel writes that he was inspired by childhood memories of poppy fields in Kent, to design urban meadows that create the same colour, energy and excitement. He trialled mixes of native and non-native flowers that provide attractive vibrant displays from April to October, and tested these out in the public realm in Sheffield. Designed for successional layering, as early species finished flowering, they are grown over by the later flowering species. An annual cut at the end of the flowering season means that these meadows can be maintained on an extensive scale.

Pictorial Meadows are available as seed mixes and turf. The Pictorial Meadows website provides comprehensive guidance on site preparation, establishment and maintenance techniques. Perennial seed mixes take a year to establish, whereas perennial turf can provide instant impact. Establishing from seed, a temporary informal hooped fence can protect establishing meadows from trampling. Annual seed mixes would be especially suitable for temporary sites.

NB. Pictorial meadows are 100% flowering plants, with no grass species. They are therefore not designed to support walking on, like amenity grass. Desire lines should be supported with mown amenity grass or paved paths to avoid trampling. Surrounding areas of Pictorial Meadows with a neatly mown edge of amenity grass will help to show that this is an intentionally wild and natural area.

Pictorial meadows are suitable for verges adjacent to a carriageway, as they are low height planting, with the bulk of planting within 60cms height, to meet any visibility splay requirements. They would also keep views open and support natural surveillance to increase feelings of safety for pedestrians and cyclists.

The Pictorial Meadows range includes mixes designed for a wide variety of site conditions, and so turf or seed should be selected to suit individual site conditions. The mixes include some with strong overall colours e.g. golden yellow in the image above, and these offer great potential to respond to the landscape themes of water, chalk and industrial heritage (page 157).

2. Mass herbaceous planting

Garden designer and nurseryman Piet Oudolf lead the way in inspiring planting approaches using mass herbaceous planting, inspired by native plant communities such as prairies and wildflower meadows. A mixture of native and non-native plants are used, in large drifts or combined in matrices, to provide a long season of interest. Components include bulbs, ornamental grasses, ferns, biennials, annuals and perennials, including species with attractive seedheads. Closeness of planting minimises spaces for weeds, and again successional layering means that earlier flowering plants are covered over by later flowering plants.

Plants are selected which will work together over the years without much intervention - long-lasting, hardy, robust species, avoiding mixes where one species will dominate, including some ephemeral plants which Prairie planting in it’s native setting, Street verge, Elk River, Minnesota, US, Prairie Restorations Inc. will fill any gaps. Maintenance can be therefore be reduced to a single cut back at the end of the season, making this approach suitable for extensive areas.

Mass herbaceous planting is typically implemented with container grown plants. An instant impact can be achieved with larger plant sizes, e.g. 5L sized. Species need to be selected to match site conditions - e.g. sunny and open (example above left and central), shady and dry under mature trees (example above right).

For street verges, plant species selected should keep the bulk of planting within 60cms height, for visibility splay requirements and natural surveillance.

3. Ground-cover planting

The use of low growing evergreen shrubs is a well established approach. This type of planting is particularly robust and is suitable for smaller verges or tree pits, or verges in streets with intense use. Single species in bold blocks work well.

This style can be developed to create a softer feel using long-season grasses, referencing the arable crop fields of the Garden of England, or with ferns or flowering shrubs. Inter-planting with spring bulbs extends the flowering season, and provides interest when plants need to be cut back at the end of winter. Plants to be low height, bulk within 60cm height, for visibility splays and to support natural surveillance.

4. Wildflower meadows

Native perennial wildflower meadows are another option. They will not have such a long flowering season as Pictorial Meadows, and take several years to establish from seed. However wildflower meadow turf is also available for instant impact, from suppliers including “Wildflower Turf” and “Lindum”.

Options include 100% wildflowers, which is not suitable to walk on, or mixes of wildflowers and grasses, which can have grass paths mown in it along desire lines.

Once established, maintenance is typically one or two cuts a year, so practical for large areas. The photo above shows a wildflower meadow with mown edge of amenity grass - framing wildflower meadows works well to define the edges so that they are interpreted as wild, and not seen as unkempt, especially during the winter.

Wildflower meadows would be suitable for areas of local parks or for street verges which won’t be walked on frequently.

5. Flowering lawns with bulb

Flowering lawns are a mixture of amenity grasses with 30% low growing wildflowers which can be mown throughout the growing season, but can still flower. Wildflowers typically include daisies, buttercups, clover and yarrow. Bulbs such as crocus, narcissus and tulips can add seasonal colour, these areas would not be mown until the bulbs have died back. The advantage of flowering lawns is that they can be walked on. As they are maintained by mowing, with spot weed-killer only, they are a relatively high maintenance option.

Flowering lawns are available as seed mixes, e.g. Emorsgate “EL1 Flowering lawn mix”, or as turf e.g. “Species rich lawn turf” from Wildflower turf.

6. Amenity grass

Amenity grass will be required for areas which people will walk on - large areas of open space in local parks, for kick-about areas, sunbathing, picnicking and informal play.

This requires regular mowing and so is a relatively high maintenance option.

Rain gardens/water sensitive design - parks and open spaces

Rain Gardens

Bringing in the blue and the green

Rain gardens can be incorporated into larger spaces such as parks in the form of softer edged ponds and swales. These planted depressions can be multi-functional, providing informal play, attractive planting, wildlife habitat, and can be used as boundary features for soft spaces to keep them clear of car parking.

Rain gardens in streets may be more constrained for space, therefore are typically more formal in layout with harder edges to guide people and cars around them.

Design needs to be developed in coordination with Drainage Engineers, and based on site conditions, such as soil permeability and rainfall, to provide adequate volume for storm-water.

Rain Gardens & Water Sensitive Design - Streets Levels 1-4

Example Rain Garden Planting Palette

Bringing in the blue and the green

Planting needs to be specified to suit the specific rain garden conditions. This includes the specific soil type / mixture within the rain garden as well as the typical inundation periods.

The following plants would be suitable for swales which vary from wet to dry. Ponds with some permanent water will need marginal and aquatic planting. Plants with year round presence should be included (e.g. Dogwood or Hard rush) and mulches (bark mulch or gravel). Phragmites australis (common reed) has nodules on its roots which clean water. However, it is very invasive, so should only be used in lakes.

Vertical & Roof Landscapes

Integrating landscape to support and enhance the public realm

Vertical Landscapes

Design teams should explore opportunities for planting on vertical surfaces of buildings, structures and retaining walls. This is especially critical in narrow public spaces such as level 4 streets and pedestrian passageways.

Four principal options are available:

• Climbing plants – twining species: These can be planted at the base of the wall, and utilises frames, trellis or wires to allow them to climb. An alternative to this system is the use of preestablished panels of ivy, which can be layered to extend the height beyond 3m.

• Climbing plants – self-clinging species: Planted at the base of the wall, these use a robust solid, textured surface to cling to. This approach may take some time to establish fully.

• Trailing plants: Trailing plants planted in irrigated troughs at the top (and intermediate intervals if needed) and allowed to hang down. The appearance can be ‘loose’

• Green-wall system: Usually modular, pre-planted panels with integral irrigation. Expensive to install and maintain, but instant and highly effective. Best suited to northerly orientations to avoid high water-use.

Designers should select the most robust and sustainable type of green wall appropriate to the situation, and should look to avoid systems with intensive maintenance requirements and high maintenance costs. Safety implications of installation and maintenance operations should be considered from the outset.

Roof Landscapes

Rooftops provide an opportunity to enhance the ‘greening’ of streets below, and provide additional habitats, climate management in highly visible higher level locations. These can be incorporated into private terraces, communal areas or public viewing areas.

The Gro Green Roof Code categorises rooftop planning as:

• Extensive green roof: Extensive roofs serve as an ecological covering that provides society with environmental benefits and the building owner with life cycle cost benefits. A lightweight, low-maintenance roof system, typically with succulents or other hardy plant species (often sedum) planted into a shallow substrate (typically less than 100 mm) that is low in nutrients. Irrigation is not normally required.

• Biodiverse roof: A roof that is similar in composition to an extensive roof, but designed specifically to create a habitat that will attract a particular flora and fauna; whether replicating the original footprint of the building or enhancing the previous habitat. This category includes a brown roof, which is a nonvegetated version. The growing medium is purposelyselected to allow indigenous plant species to inhabit the roof.

• Semi intensive green roof: An intermediate green roof type that can include characteristics of both extensive and intensive roofs. Typically requiring a depth of substrate between 100 mm to 200 mm, a wider range of plants can be included, compared to extensive roofs, including shrubs and woody plants. Irrigation and maintenance requirements are dependent upon the plant species installed. Intensive green roof: A version of a green roof, often referred to as a roof garden, which provides benefits akin to a small urban park or domestic garden. Designed primarily for recreational use, intensive roofs are typically configured with 200 mm+ of substrate and often require regular maintenance and irrigation. Design teams should explore ways of optimising roof space to establish useful amenity and habitat areas according to the four categories of green roof described in ‘Gro’. Good practice described within Gro should normally be followed in the establishment and management of green roofs. Installation and maintenance ease and safety should be considered from the outset.