Conservation Comment: Wilding your garden

Annual euphorbia and spur valerian plants in Phil Thomsen's garden flower profusely over spring. Photo / Phil Thomsen

In previous articles, I’ve promoted the development of home gardens to embrace conservation values – adding organic matter to soil to sequester carbon, composting organic material, encouraging beneficial insects, and providing a refuge for native birds. In this article, I discuss the use of wildflowers in the garden, and the advantages of this practice.

Wildflowers have multiple benefits. Many highly hybridised plants have been bred for shape or size, and in some cases have lost the ability to be pollinated naturally. Wildflowers, on the other hand, produce copious pollen and nectar, and attract a host of beneficial insects. They are also trouble-free, having natural resistance to pests and diseases. They generally produce prodigious quantities of organic matter which, after flowering, can be composted or returned to the soil to improve it. Finally, they are very refreshing to the eye and spirit, improving mental health by creating a fabulous, natural garden ambience.

Wildflower seeds are available through several seed merchants, and usually include a range of plant types, especially selected to suit New Zealand conditions. Most of the species come from temperate zones, so are suited to local conditions. Some originate in relatively dry climates, such as Australia or California, so don’t need a lot of watering. They are generally seasonal annuals, although some mixtures include perennials.

Personally, I have never bought the commercial seed packets. I have scrounged and encouraged species that readily self-seed, and work well in my situation. Borage is one of my favourites; it flowers for a long period, has culinary uses, its blue/mauve flowers are beloved by bees and other pollinators, and it self-seeds readily. Each plant covers a lot of ground with its flannelly leaves, suppressing weed germination.

Spur valerian has red flowers which are also very popular with butterflies and bees. I also have annual euphorbia, daisies, and purple linaria. These three plants grow through the winter and flower through spring.

After I have chopped out the spring flowers, lychnis and sunflowers come to the fore. I don’t remove the sunflower plants until the greenfinches have fully feasted on the copious amounts of seeds. A self-seeded fennel plant appeared in my garden a couple of years ago. It has great umbels of small yellow flowers which attract parasitoid wasps. Fennel tends to be over-vigorous for a home garden, so I do thin the plant back to a single stem, to keep it in bounds. I also have self-seeding cinerarias and primulas which flower through winter.

When the plants have completed their peak flowering period, and seed is being distributed, I remove the plants using the “chop and drop” method. I cut them off at ground level, and spread the remains over the soil surface. This does create a bit of a mess in the short-term; however, I spread grass clippings thinly over the remnants; this disguises them and encourages decomposition. In this way, the foliage and stems provide a useful mulch, which protects the soil surface, retains moisture, and prevents most weeds from emerging. What does germinate is a mixture of weeds and wildflowers, so I simply remove the former, giving the wildflowers room to develop.

This organic matter breaks down quite quickly, helping to develop humus and a healthy soil structure; nutrients are also released. I never introduce any fertiliser, whether artificial or natural into my garden, yet still get impressive growth, as well as fruit and vegetable production.