There is a huge selection of perennials that can add interest and colour to the garden in summer and they come in all shapes and sizes.
They often make a garden theme, such as a cottage garden where they can be the companions for more permanent plants such as roses and trees.
Herbaceous perennials such as Hosta and Astilbe emerge during spring, flower in summer and die down and become dormant in winter, they enjoy cool garden conditions.
Perennials can complement many trees, shrubs, roses, annual flowers and bulbs.
Many provide excellent flowers for indoor use. Others have attractive foliage in bronze, yellow-green, grey and silver.
Perennials prefer some good compost added to the soil with slow-release general fertiliser like Ican Slow Food when preparing to plant.
Some unusual, rare and common perennials to look out for include:
Bidens
These have increased in popularity for the recurring flower power that they offer for many months each year.
There are numerous varieties that generally form small mounding plants approximately 30cm high by 50cm wide.
They are ideal for pots and larger hanging baskets, as the growth habit cascades attractively over the side of the pot.
Bearded iris
These have fleshy rhizome-type roots and generally leaves on all year round.
During the late spring and early summer period, they produce spectacular flower spikes.
They grow best in a well-drained situation. There are numerous flower colours and patterns in almost every colour imaginable.
Delphinium
These eye-catching perennials produce tall spires of blooms generally ranging from 50-80cm in height during the summer months.
The root system develops and expands each year and the plants will carry an increasing number of blooms.
Thanks to years of breeding and multiple crosses, there are a wide array of colours available from white, pink, purple, blue in varying shades.
Best in full sun.
Lily of the Valley
Sought after for its fragrance, this bulbous perennial is dormant all winter, popping into life in September each year, producing flower spikes in October.
Leaves continue during summer before going dormant for the autumn and winter.
The flower stems have numerous fragrant, dainty blooms.
Growing approximately 15-20cm high. Great in part shade positions under trees.
Osteospermum
Also known as cape daisies, these plants are hardy to conditions ranging from coastal wind and hot sun to semi-shady positions.
They boast a continuous flowering habit with blooms almost year-round.
They are drought-tolerant and look great in containers and garden situations.
Geranium and Pelargonium
These plants are ideal and easily maintained perennial plants for pots, window boxes and hanging baskets as well as in garden plots.
They thrive in most soils in sunny positions. Regular pruning after flowering keeps the plants compact.
Popular flower colours are red, white, pink and mauve. Ivy (climbing) geraniums have long stems for trailing over walls and fences or for trailing over banks.
They are also suitable for hanging baskets.
The Pac range are exceptionally good, with exceptional ability to repeat flower with high intensity throughout most of the year while maintaining an attractive compact and bushy growth habit.
Heuchera
Grow well in full shade to half shade position, moist soils, approximately 30x45cm.
They produce stunning foliage to add year-round colour in gardens with clusters of small coral pink or white bells in spring and autumn.
They love shade so are ideally planted under trees and shrubs or on the shady side of the house.
Look out for varieties: “Plum Power”, “Northern Exposure Amber”, and “Black Taffeta” – all stunning.
Hosta
Hosta grow well in full shade to semi-shade positions most in the 25-40cm range.
They form handsome leaf colours and textures from bright chartreuse (yellow and green) through forest greens, icy blues and silver greys and cream or yellow variegated foliage forms.
They have small bell-shaped white or lilac flowers, sometimes fragrant in summer.
They thrive in moist, well-drained soils with plenty of compost added.
Feed in the spring and mulch with compost, straw or similar to keep them cool and moist.
Always be ready with slug and snail bait from early spring as they are often subject to voracious attacks.
Gareth Carter is the general manager of Springvale Garden Centre in Whanganui.
