How to Grow Perennial Ornamental Plants

How to Grow Perennial Ornamental Plants

How to Grow Perennial Ornamental Plants  Some of the most useful plants for an unheated greenhouse are hardy spring-flowering shrubs and climbers, such as camellias, azaleas, and jasmine, and herbaceous plants such as Dicentra and pasque flowers (Pulsatilla).

Grow these in pots and bring them into the greenhouse in autumn: they will bloom earlier and better than they do outside, where the flowers are easily ruined by frost. In summer, sink the pots in a sheltered, semi-shaded part of the garden to make room for summer plants.

Many popular summer pot plants such as geraniums and fuchsias are not fully hardy, and may not overwinter in an unheated greenhouse. However, they are worth growing for a reliable splash of colour, provided that you have suitable space indoors to keep them during the coldest weather. Alternatively, take cuttings and overwinter small plants in a heated propagator. Similarly, a few chrysanthemum stools overwintered in a frost-free place will provide plenty of cuttings for new plants in spring.

Most foliage plants are also frost-tender, but ivies and some hardy ferns grow well and need not be as dull as you might think!

Climbers are more difficult to move, but slightly tender species such as passion flowers (Passiflora) and the scented jasmines (Jasminum) could be permanent features if you are prepared to give them space.


Fuchsias will bloom all summer and well into the autumn. When they start into growth in spring, pinch back the young shoots once or twice to make the plant bushy. In summer, water the plants freely and keep in a lightly shaded, well-ventilated part of the greenhouse. Reduce the amount of water in autumn, and when they have lost their leaves put them in a frost-free place for the winter. Some fuchsia varieties are hardy enough to survive in an unheated greenhouse if the pots are plunged into sand or other insulating material. In spring, pot them into a fairly nutrient-rich potting compost and cut the old growth back by half.


Ivies (Hedera) can provide a background of foliage at all times of year. Some varieties have deeply cut, heart-shaped or crinkled leaves, others have white, cream, or light-green variegations. They do best when kept shaded from strong sunlight and moved outdoors during the hottest months.


Camellias have large flowers very early in spring, which may be single or double, in white, red, or shades of pink depending upon the variety. Keep them in large pots or tubs, bringing them into the greenhouse in late autumn and putting them back outdoors in a fairly shady part of the garden after they have flowered. Never let them dry out. Water with rain-water in hard-water areas and use an acid compost when repotting.

Pasque flowers

Pasque flowers in a greenhouse should give you a display of purple-crimson, pink, or white flowers for early spring. Pot up the plants in a well-drained compost. Keep them in the greenhouse from late autumn until after flowering, then stand them outside in the summer. Avoid overwatering.

Climbing jasmine

J. polyanthum, sold as a winter-flowering houseplant, is hardy enough for an unheated greenhouse in mild areas. Plant it in a large pot with a tripod of canes or in the greenhouse border. Its tubular white flowers will scent the whole greenhouse in early spring. Cut the plant hard back after flowering to keep it in check. In cold areas choose the summer jasmine, J. officinale.


Late-flowering chrysanthemums bloom from early autumn onwards, surviving in an unheated but insulated greenhouse until there is a hard frost. In mild areas they could provide you with cut flowers until early winter. When the flowers have finished, cut back all the stems. Keep some of the dormant plants, or stools, to overwinter in a frost-free place, in order to provide plenty of shoots for cuttings the following spring.

29. November 2010 by Dave Pinkney
Categories: Perennials, Plants & Trees | Tags: | Comments Off on How to Grow Perennial Ornamental Plants


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