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All ratings refer to the UK growing conditions unless otherwise stated. Minimum
temperature ranges (in degrees C) are shown in brackets
While we update our systems with the new hardiness ratings you may still see old
hardiness ratings in your search results. These are denoted as 'Old'.
For full details of the hardiness ratings see
AGM plants have been through a rigorous trial and assessment programme. They are:
H. albicans is a dense, rounded, evergreen dwarf shrub forming a broad mound with small, glaucous, oblong leaves and short, dense spikes of white flowers in early summer
H. hulkeana is a small evergreen shrub of open growth, with glossy, toothed oval leaves, often red-edged. Flowers pale lilac, in very large, open panicles
H. rakaiensis is a compact, rounded evergreen small shrub to 90cm in height, with small, bright green leaves and short spikes of white flowers from early summer
H. salicifolia is a tough evergreen shrub of rather upright habit, with willow-like, narrowly lance-shaped leaves to 12cm long, and long drooping racemes of white or pale blue flowers in summer
H. vernicosa is a rounded shrub of compact habit, with small, very glossy dark green leaves and axillary racemes of small white or very pale blue flowers in early summer
P. perfoliata is a sprawling, evergreen woody-based perennial to 70cm in height, with broadly ovate, leathery, bright blue-green leaves 3-5cm in length, and axillary racemes of clear blue flowers 10mm across, in late summer
'Sapphire' is an evergreen shrub with narrow dark green leaves tinged purple, and short racemes of rosy-mauve flowers in summer
'Margret' is a compact, rounded evergreen shrub with bright green foliage and light blue flowers in short racemes in early summer, often repeating in early autumn
'Neil's Choice' is a lax evergreen shrub with purplish stems bearing narrow leaves, the margins and midrib purple, and dense narrow racemes of violet flowers in summer and early autumn
'Mrs Winder' is a spreading evergreen small shrub with narrow, dark green leaves, the youngest tinged with reddish-brown. Flowers small, violet-blue, in racemes to 7cm in length
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