Dig It – March tips from the Secret Gardener

fritillaries on umbellifer

The Carrot family - Apiaceae or Umbelliferae - includes some of the best pollinator plants as well as some of the best cut flowers. One of the most recognisable plants in this family is Cow Parsley Anthriscus sylvestris, which lines the roadsides with a sea of white from April to June.

Umbellifers are so named because of the umbrella-like arrangement of flowers they produce. The tall stems with feathery foliage have lacy, airy, flower heads, made of a mass of tiny, five-petalled flowers. The flat flower heads make a great landing pad for insects such as butterflies, moths, hoverflies, wasps and flies and they are a popular nectar (carbohydrate) or pollen (protein) source. Hoverflies are useful insects to encourage in your garden as the larvae of most species feed on aphids.

In the wild, umbellifers are nectar sources for butterflies such as hairstreaks, fritillaries and skippers.The British Swallowtail butterfly breeds only in the Norfolk Broads and is restricted to a single caterpillar foodplant, Milk-parsley Thyselium palustre, whereas Continental Swallowtails feed on various umbellifers.

Sulphur Pearl on Umbellifer

One moth that has been spotted nectaring on umbellifers is the Yellow Shell, which is found in fields, meadows and gardens throughout the British Isles. It is frequently disturbed during the day and flies from dusk onwards from May to August. Cow Parsley is a foodplant for some moth caterpillars such as Double Square-spot Xestia triangulum and Single-dotted Wave Idaea dimidiata. Pignut Conopodium majus is used by Chimney Sweeper Odezia atrata caterpillars and Sulphur Pearl Sitochroa palealis caterpillars feed particularly on Wild Carrot Daucus carota.

The umbellifer family ranges from edible plants to those that are highly poisonous. Edible plants include root vegetables, such as Carrot and Parsnip, and herbs with aromatic leaves like Fennel, Parsley, Coriander and Dill. At the other extreme, Hemlock and Hemlock Water-dropwort are some of the most toxic plants in Britain and Giant Hogweed sap can cause burns or rashes. In ancient Greece, Hemlock was used to poison condemned prisoners, with the most famous victim being the philosopher Socrates.

In spite of this, there are many umbellifers which make great garden plants. The tall, delicate flowers are a great addition to the back of a border, especially when grown in groups or interspersed with other plants such as Scabious. They also make useful cut flowers, with good vase life, working as pretty fillers amongst the main blooms of the arrangement. Many umbellifers have white flowers, but some are pink, yellow or green.

You can sow seeds for the following plants over the next few months:

Small Tortoiseshell on UmbelliferIf you want a more delicate, garden version of Cow Parsley, then try Bullwort or Bishop's Flower Ammi majus, which has lacy, white flowers on 90cm stems from June to August, 12 weeks from sowing in late spring or early summer. Additionally, you can also sow straight into the ground in the autumn which will produce larger, more prolific plants the following summer, which flower earlier. Hardy annuals can withstand a little frost and will survive the winter without protection unless in a very cold area. Note: take care as the sap can burn sensitive skin when exposed to bright sunlight.

Toothpick-plant Ammi visnaga is a more substantial form, with dense yet delicate white and green domed flowers from June to September, 12 weeks after sowing in March to May. If sown in mid-spring they will reach 90cm but if sown in late summer they could reach 1.8m high the following year.

White Lace Flower Orlaya grandiflora has fuller flowers from June to September. This hardy annual will reach 45 to 60cm. Sow under cover March to April or sow direct in April for summer flowering, or in autumn for earlier flowers the following year.

For acid-green flowers from June to October, try False Fennel Ridolfia segetum. Sow indoors in March to April and/or August to September. Or sow direct in a sunny position from mid-spring. It flowers 12 weeks from spring sowing, reaching 1m tall.

Herbs:

Dill Anethum Graveolens is a 60cm-high, hardy annual. Its leaves are used to add flavouring to pickles or with vegetables, salads and fish dishes for cooking; its flowers can be used to decorate salads. Sow direct, from April to May, where it is to grow, as dill has a long taproot and dislikes being transplanted. It will have acid-green flowers from July to October, 12 weeks after spring sowing. It will self-seed freely.

Fennel Foeniculum vulgare is a hardy, perennial, 1m-high, aromatic herb with feathery leaves and yellow flowers from July to August. The bulb, foliage, and seeds all have culinary or medicinal uses, with the dried seeds having an aniseed flavour. Sow direct, from April to May, where it is to grow. Remove the flower heads if you don’t want them to self-seed.

Fennel can be used as a foodplant by caterpillars of the Mouse Moth Amphipyra tragopoginis, which utilises a wide range of wild and cultivated herbaceous plants and is common throughout most of the UK. It overwinters as an egg and is a caterpillar from April to June, pupating in a cocoon at or just below the ground. The adults are on the wing from July to September. If disturbed, they will scuttle away like a mouse rather than taking flight.

In your garden you are more likely to see Small Tortoiseshell, Gatekeeper and Meadow Brown nectaring than hairstreak butterflies. We would be interested to know how many species you attract to your umbellifers. 

Happy Gardening!

The Secret Gardener