10 AGM-winning conservatory shrubs and climbers

Plantsman Graham Rice picks 10 of his favourites, all winners of the RHS Award of Garden Merit, for growing under glass

In the conservatory, where pot plants and patio plants and plants in small or medium-sized pots come and go with the seasons, it’s the shrubs and climbers which give the space its structure and play a significant role in establishing its character. So it’s important to choose wisely, especially as space for large plants is bound to be limited.

This selection, all winners of the prestigious RHS Award of Garden Merit, includes climbers and shrubs which are at their best across the seasons. When pruned, all can be kept to a stem length of 2-3m (6ft6in to 10ft); without pruning, most will over-dominate.

H1 - H7 indicated the new hardiness ratings

Full details of hardiness ratings (510kB pdf)


Plumbago auriculata

The blue of these flowers is such a lovely summer sky colour that I always like to see it, in the summer garden or the conservatory. A scrambling shrub, best tied in as a climber or grown in a pot and moved to the patio for summer. Prune back hard in spring to neaten the plant and encourage more flowers. Needs a temperature above 0°C. H2.

Trachelospermum asiaticum

Hardier than the other climbers recommended here, so good in an unheated sunroom, the highly scented creamy flowers open amongst glossy leaves in summer and early autumn. This twining climber can be cut back in early spring and moved outside for summer. Find out more on the RHS advice pages. Hardy to -10°C but hates winter wet. H4.

Stephanotis floribunda

Another twiner grown for its fragrance as well as its colour, the waxy 5cm (2in) white flowers open from spring to autumn amongst dark, glossy foliage. Appreciates a more humid atmosphere than many conservatory plants, and needs a temperature of above 10°C. Shorten main shoots by half in spring, but do not cut back hard. Find out more on the RHS advice pages H1b.

Passiflora × exoniensis

This impressive hybrid passion flower, clinging by tendrils, produces vivid nodding rosy red, 10cm (4in) flowers in summer and autumn which conveniently look down at you from the conservatory roof. These are often followed by 9cm (3.5in) edible banana-like fruits. Needs a temperature above 1°C and happy outside in summer. Prune in early spring to keep to size. H2.

Pandorea jasminoides

In spring and summer, and even into autumn, this dramatic scented twiner produces flared, tubular white flowers which are stained magenta pink in the throat amongst glossy, handsomely divided leaves. Flowering most prolifically when confined to a pot, it can be pruned after flowering to keep it manageable. Needs a temperature above 5°C. H1c.

Jasminum azoricum

The 3cm (1.2in) white flowers of this Madeiran native open from purplish buds mainly towards the end of summer and, like primroses, some plants carry “pin” flowers and others “thrum”. Otherwise, they are identical and their scent is delightful. It makes a twining climber which needs tying in regularly but is relatively tough and will take 0°C in winter. Prune in spring. H2.

Hibbertia scandens

A vigorous climber with twining stems, the bright yellow, 6cm (2.4in) flowers - superficially rather like those of hypericums - sit amongst dark leathery foliage in summer. The shoots need tying in regularly to avoid the plant becoming too tangled and unmanageable. Usually needs a temperature above 5°C, but will grow outside along the Cornish coast. Prune after flowering. H1c.

Gardenia jasminoides

The fragrance of the ivory white flowers of this bushy shrub is exceptional and the 8cm (3in) blooms appear singly or in small clusters at the tips of the shoots or in the upper leaf joints. They open over many weeks in summer and autumn amongst glossy, dark green foliage. Best in a temperature above 5°C. Prune in spring. H1c.

Citrus × microcarpa

The calamondin produces large numbers of small, 3cm (1.2in) orange fruits whose skin is sweet but whose fruit is rather tart. Excellent as marmalade, the fruits can also be frozen whole as an interesting variant on the humble ice cube. The fruits are preceded by fragrant white flowers in spring and summer. Best in a temperature above 5°C. Prune to size in late winter. H1c.

Brugmansia arborea 'Knightii'

This bold, gorgeous, and well scented shrub features large white flowers up to 15cm (6in) long with one flower held inside another like a hose-in-hose primrose. Flowering from late spring right into the autumn, cut back hard in spring to prevent plants becoming too large but flowering will be delayed. All parts are toxic if eaten. Find out more on the RHS advice pages.  H1c.


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