During this hot weather period, our trees have been under stress. We ask you not to sit under our trees or enter roped off areas due to the risk of sudden limb drop. Areas including the Lower Woodland Walk, Learning Centre wildlife and picnic areas, and Copper Shelter are closed at this time.

Plant of the month: juniper 'Blue Star'

Small, tough and colourful, this low-growing juniper makes great groundcover for hot, sunny sites and combines well with many other plants

Juniperus squamata 'Blue Star' AGM - or the flaky juniper - is a compact conifer making a low shrub up to 50cm high and 1m spread. The densely packed, prickly foliage is a bright blue-grey with the clusters of awl-shaped needles on top of the stems resembling tiny stars.
This plant needs to be grown in well-drained soil but doesn't need pruning unless you want to keep it in a very small space or to remove the odd misplaced branch. The only tender loving care this tough shrub needs is to keep it moist for the first year after planting to encourage it to establish well: once established it is very drought tolerant.

‘Blue Star’ makes a good ground cover on hot, sunny sites as it tends to grow out rather than up. Also use for interest in a large rock garden, or, as at Rosemoor, in a heather garden.

Colourful companions

Plants that change colour through the seasons, whether evergreen or deciduous, will prevent the planting from becoming static and looking the same all year. For example, at Rosemoor we have combined ‘Blue Star’ with heather Calluna vulgaris 'Blazeaway' which has yellow foliage in spring, darkens to green in summer and then in autumn and winter it turns orange and red. As a bonus, the lavender flowers harmonise well with the blue of the juniper foliage.
Grow alongside plants with bright yellow foliage such as the tree heath Erica arborea ‘Albert’s Gold’ AGM or winter heather Erica ‘Golden Starlet’ AGM for a colourful effect as good as any flower combination.

To lighten the hard spikiness of the juniper, add a low growing grass to the mix, for example, Mexican feather grass, Stipa tenuissima, with its soft, airy foliage makes an effective textural contrast. In our heather beds, ‘Blue Star’ grows near to the cone-shaped Alberta srpuce, Picea glauca 'Conica' AGM which contrasts with the low growing and spreading juniper.

Conifers can be difficult to place in the garden, but Juniperus squamata 'Blue Star' AGM makes a useful ground cover, with that unexpected but welcome splash of blue during the winter months.

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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.