July's Plant of the Month

A hardy, South African aloe is a permanent resident in the Dry Garden at RHS Garden Hyde Hall

A closeup of the flower head of Aloe striatulaThe Dry Garden at RHS Garden Hyde Hall is situated on a warm, sunny slope, and we have always experimented with the plants we grow there with the aim of trying as wide a range as possible, particularly those that are not hardy enough to survive in other parts of the garden. A plant we have grown for several years, and that looks its best now, is the hardy aloe Aloe striatula (right).

Most aloes are tender and many cannot be grown outdoors in the UK, but this species is tough and will tolerate a few degrees of cold. It comes from South Africa but grows high in the mountains and will therefore survive to around -5°C (23°F). However, the soil needs to be well-drained and it needs to be planted in a warm position, away from cold winds.

The Dry Garden is the ideal spot as it is south facing and receives sun throughout the day; the aloe has even survived temperatures of -8°C (18°F). However, when it gets this cold, it is liable to lose all of its top growth, but we are able to cut it back to the base to allow new growth to emerge from the rootstock.

The hardy aloe behaves almost like a sub-shrub and it will develop a woody base. In its native habitat it will grow up to 2m (6½ft) tall, although the colder winters in the UK usually prevent it from growing this high here. The stems have very distinctive dark green stripes along them and the leaves are curved inwards with small white teeth along their margins. The flowers emerge in high summer and resemble a flame as they are tightly packed on each head which become narrower towards the top. The flowers are green tipped to begin with, turning bright buttery yellow with orange anthers as they open, making a striking sight.

Aloe striatula growing against a boulder in the Dry Garden at  RHS Garden Hyde HallIn the Dry Garden, Aloe striatula grows well against a boulder which gives it extra protection and it acts as a good backdrop (left). Other drought tolerant favourites that we grow alongside it are plants such as cultivars of sea holly including Eryngium bourgatii ‘Oxford Blue’ that has deep blue thistle-like flower heads, loved by bees and insects.

Perennial salvias also add great colour at this time of year: two selections to look out for are Salvia × sylvestris ‘Mainacht’ and Salvia nemorosa ‘Caradonna’ both of which have vivid purple blooms. Lastly, as a contrast, why not try a native flower alongside the exotic aloe, the yellow horned poppy (Glaucium flavum) grows very well in our Dry Garden where it enjoys the well-drained soil and pebble mulch.

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