Meet the Editors

Tom Nielsen, from Biocentric Plants, outlines his philosophy for plant selection and planting design, using selections of native or near native plants that are excellent for wildlife as well as humans. - 03 May 2024

In selecting the plants that I grow in the nursery or use in my designs, I use a variety of editing tools. The first is the most common one used in horticulture: Aesthetics. Do I like the plant? Do I find it beautiful or does it play an important role in making an overall planting beautiful? Mostly the answer is yes, certainly where species plants are concerned.

Often this is where people stop. The temptation to do whatever it takes to grow the plants you want is too much for some people and so borders are double dug and improved with compost, plants with wildly different needs and behaviours are planted together and failure of the planting is concealed by regular replacement of plants to bring about the desired effect.

The next one is the key editor for me, and the question at the heart of all sustainable horticulture: Does the plant want to grow there? Does it get the right amount of sun? Will it have enough nutrients on the underlying soil? Will hard frosts kill it? Will it rot away in winter rains? Is it particularly delectable to molluscs or rodents?

It is possible for a plant to provide the right answers to all of these questions and for it still to not thrive. If it droops sulkily and fails to flower most years it is not merely a question of plant survival but a waste of space that could be filled with something that would grow joyfully. Some things also grow a little too joyfully and you need to decide whether the hours of weeding and thinning are worth the effect of say growing Leucanthemum vulgaris in a gravel garden or whether you might get the same white daisy effect with a better behaved Tanacetum corymbosum or Argyranthemum frutescens.

The final editor for me is the question of what the plant gives to the ecosystem around it. Does it have flowers accessible to insects particularly to extend the flowering seasons at both ends of the year for bees? Does it host the larval stage of butterflies and moths? Do its stems provide over-winter shelter? Do its roots stabilise the soil effectively, preventing erosion? All of these are particularly valid questions in the years we are living through and should guide our choices for future plantings.

The days of specimen plants in a sea of mulched soil are behind us. Our plantings should now fill the available space by increasing planting density covering the soil surface reducing evaporation of water and limiting opportunities for weeds to break in. We can also increase the density by using different plant heights, growth and flowering times, root profiles to increase the diversity of the planting giving more bang for your buck for us and the wildlife.

I like to look at wild areas and then transpose them to garden situations based on their ecological archetype. For example, a wild hedgerow bank can provide an example of what might work in a narrow well drained shady border, a wildflower meadow might give suggestions for an open sunny border. Looking closely at the parts that make up these archetypes can allow us to construct new plantings that might work at garden scale.

One thing that leaps out at you when looking at natural spaces is that grass and grass-like monocots such as sedges and rushes always features heavily. You could say that they are the structural backbone or matrix of most ecosystems. I always include a high proportion of grass-like plants in any planting I undertake and luckily there are great plants for every situation you might desire. In hot sun, I love the Stipa as dramatic long-lasting structural plants. The well-known Stipa gigantea is common enough with large golden flowerheads from an needle-thin leafed evergreen clump, but I’ve also fallen in love with Stipa ichu and S. pseudoichu from South America with their mobile shining silver whiplike seedheads. I give Stipa tenuissima a miss these days as it often looks very sorry for itself in our damp south west winters.

Lower growing in dry sun, the native Koeleria glauca is an excellent low clump former with short fluffy seedheads. Molinea caerulea, the purple moor grass, forms the matrix of many of my plantings. The tall airy M. ‘Transparent’ or ‘Skyracer’ are well known but the shorter more natural forms are really excellent plants for damp or dry conditions in full sun or part shade. I have several selections in the nursery and self seeding in the planting always gives the variety that makes things look naturalistic.Deschampsia caespitosa is another native matrix plant but I’ve found it more capricious than Molinia. If it doesn’t like where you plant it, it will quickly die out while if it does you will have too much of it! In shade, the Luzulas (nivea and luzuloides) are superb.

Many natural plantings also feature umbels heaving, particularly in early summer. Luckily there are many excellent options that we can use to bring this effect into our plantings. Whilst always admiring of the huge white flowerheads of Hogweed, not many welcome it into our gardens, not least due to the vicious burns it can give us. I’ve found that visually, Achillea grandiflora, the giant Eastern European millefoil, makes a good substitute whilst also adored by insects. Standing at 1.5m with domed white flowerheads this is the only Achillea I grow as I find the brightly coloured cultivars don’t last long in the ground and need regular propagation and replacement. Other good perennial umbels are Chaerophyllum hirsatum ‘Roseum’, Myrrhis odorata and Selinum wallichianum, and I’m currently trialling a host of others to see what does best.

Along with the umbels and grasses, legumes are often well represented, usually in the forms of clovers and vetches. These are excellent plants for nutrient poor soil as they can fix their own nitrogen from the air and thus grow heartily while other plants may struggle. The giant clovers, Trifolium rubens, and T. ochroleuca are robust perennials flowering at 40cm with tufty pink or creamy white flowers loved by bees. They repeat flower well if chopped back or provide spiky brown seedheads if left.

Knapweeds are common plants in meadows or road verges, usually Centaurea nigra, but also the more visually attractive C. scabiosa. The latter should be used more often in gardens as it is an excellent plant. But other knapweeds such as C. atropurpurea, C. ruthenica, and C. macrocephela give other form and colour options for poor dry ground in full sun. The more commonly grown C. montana is a lower growing, more sprawling perennial available in a range of colours but it can be an unattractive plant after flowering.

 

The wiry pincushions of scabious, most commonly seen in the form of Knautia arvensis in British fields and verges, are excellent robust perennials and adored by insects. You can use Knautia arvensis in plantings successfully and add the deep red K. macedonica for contrast and interest,  whilst the Cephalarias C. gigantea and C. dipsacoides provide height and creamy white swarms of flowers. In poor, dry soil in full sun Scabiosa ochroleuca puts forth a wiry haze of white pincushions at 50cm.

In damper soil, the native Eupatorium cannibinum is often found around ditches and low ground in large stands. Whilst attractive, the American Eupatoriums (now Eutrochium – E. maculatum and purpureum) and cultivars such as E. ‘Riesenschim’ are more visually striking with dark stems and deep pink flowerheads covered in bees and butterflies.

 

Filling the lower areas are some upgrades on other small native plants such as Plantago major ‘Rubrifolia’ for the common green kind, Prunella grandiflora in place at the flowering lawn stalwart Prunella vulgaris and Ranunculus acris ‘Citrinus’ for the normal yellow buttercup. Its also easy to find room for a few Geranium ‘Bill Wallis’ to fill the gaps. Where it feels right, don’t be afraid to use other more exotic plants to bring something extra to the planting. I use Eryngiums (primarily those from South America), Veronicastums and Salvias that bring something else in terms of flowering or structure without being too jarring in terms of contrast.

Tom Nielsen owns Biocentic Plants, a small family-run nursery in West Somerset that grows a select range of herbaceous perennials, grasses and shrubs. Many of these are selections of native or near native plants that are excellent for wildlife as well as humans.

Website: www.biocentric.org.uk/biocentric-plants/