Annuals are plants that complete their life cycle in one season, while biennials need two seasons, producing leaves in the first year, flowers and seeds in the second.
Lavatera trimestris is an annual cousin of the perennial mallow, with larger flowers - they may be 10cm/4in across - which are excellent for cutting. Both pink and white forms are available.
This biennial member of the forget-me-not family bears sprays of tiny, fragrant blue flowers that provide drifts of colour in the border. They can be naturalized in woodland or raised under glass for cut flowers.
Asperula orientalis is a neat, low-growing plant with attractive star-shaped leaves and clusters of tiny blue flowers that are lightly scented. Good at the front of the border or for cutting, this species may also be grown as a pot plant. a
Lobelia erinus, a perennial treated as an annual, is an indispensable element in summer bedding schemes, while the trailing varieties are invaluable in window boxes and hanging baskets.
Although this member of the dianthus family is a perennial, D. barbatus, or Sweet William, gives best results when grown as a biennial. The dense flat heads of fragrant flowers range in colour from white through pink to deep cherry red.
Molucella laevis or bells-of-Ireland - Its green spires add height and provide the perfect foil for more showy plants. Each tiny white flower is surrounded by a light green, bowl-shaped calyx. No named varieties are available.
There are two types of annual delphiniums, namely D. ajacis, known as rocket larkspur, and D. consolida, the common larkspur. Both are typical cottage garden plants, their tall spikes clothed with flowers of blue, white, pink or purple.
The China aster, Callistephus chinensis, bears chrysanthemum like blooms from high summer to the first frosts. They are bushy plants with flowers in all tones of pink, red and purple or white;