The Urban Botanics Glossary: Perennials and Annuals

Published 9th February 2017 by Michelle

Welcome to the first Urban Botanics glossary entry. In this new series of posts we’ll succinctly explain key gardening jargon so you can take your urban gardening to the next level. Armed with a few key definitions you’ll be confident in selecting plants and flowers that are most appropriate for your urban garden, and ready to look after them so they keep looking beautiful. Since this is our first glossary entry, we’ve got a double bill special; covering both annuals and perennials.

Hydrangea - a hardy perennial

P is for… Perennials

Technically and biologically perennial plants are all plants which live for more than two years. In the gardening world the term tends to refer to plants which meet this definition but which aren’t trees, shrubs, bulbs, or fruit/veg/herbs.

This grouping of plants is divided into two main categories:

> Hardy perennials – plants that live for more than two years and can survive through frosts. Many do this by dying back to below ground level over winter and then re-growing above ground in the spring.

Some examples: verbascum, agapanthus, lavender, lupins, oriental poppies, peonies, echinacea, bleeding heart, hydrangeas.

> Tender or Half–hardy perennials – plants that live for more than two years but which die if exposed to heavy frost (below 0 degrees), and therefore must be given protection over winter. This can be done by wrapping the plant pot in bubble wrap or garden fleece and moving it to a sheltered spot. Alternatively you can bring the plant indoors, preferably to a room that isn’t heated, during the coldest weeks of winter.

Some examples: most dahlias, most pelargoniums, some salvias, Gaura lindheimeri, chocolate cosmos.

Verbascum - a hardy perennial

Chocolate Cosmos - a tender or half-hardy perennial

Dahlia - a tender or half-hardy perennial

A is for… Annuals

Annual plants are plants that live for one year. This grouping of plants is divided into two main categories in the gardening world:

> Hardy annuals – plants that live for one year and can survive frost, and can therefore be sown/planted outside before the last frost (in early spring).

Some examples: sunflowers, cornflowers, nigella love-in-a-mist, ladybird poppies, common poppies, californian poppies, sweet peas.

> Half–hardy annuals – plants that live for one year but which die if exposed to frost, and therefore must be sown/planted outside after the last frost (in late spring / early summer).

Some examples: nasturtiums, nicotiana, Cosmos bipinnatus.

Nigella love-in-a-mist - a hardy annual

Cornflowers - a hardy annual

Ladybird poppies - a hardy annual

Nasturtiums - a half-hardy annual

I hope you find these posts useful, in future we’ll be covering lots of terms including bedding plants, variegated leaves, bulbs, dead-heading, weeding and tubers. Bit by bit you’ll learn the lingo and become an expert urban gardener!

Till next time,

Michelle x