Gardening Column

Garden Blooms Nursery
A small independent nursery specialising in herbaceous perennials

Gardening Column May 2009

Annual, Biennial or Perennial, Hardy or Tender?

I don't understand the difference!

Annuals

The seed is sown either by you or by the plant shedding it's seed naturally. It germinates and grows leaves, flowers and produces it's seed all during one season. In this country that usually means between spring and autumn. If annuals are hardy (see below) they can be sown in autumn to flower the following year. If they are tender, as a lot of typical bedding plants are, they are best sown in spring as they will not tolerate frost.

Biennials

The seed sowing process is the same as for annuals but in the first season the plant only grows leaves. If it is an evergreen plant (one which doesn't lose it's leaves in winter) it will stay like this until the following season (or year in this country) when it will flower, set seed and then usually die.

Perennials

These behave like biennials but don't die after they have flowered. They often die down in winter so there is nothing to see but then reappear in the following spring. The clump then generally grows bigger over the following years.

Hardy

This just means that the plant can tolerate a certain amount of cold, often as low as -20°C. The plant can be annual, biennial or perennial. Some annuals can be sown in autumn, survive the winter and flower the following year.

Tender

How tender? Well it depends on lots of things, where you live in the country, how high you are above sea level and how exposed the plant is. Tender can mean anything from 0°C upwards. Many tropical plants for example need at least 15°C and are most suited to the conservatory or a heated greenhouse. A lot of tender plants however will survive colder temperatures than often indicated as long as they are kept dry in winter. A good example of this is the Gazania.