Blue Foliage Plants

Following on from last week’s article concerning silver toned foliage, this week we will be covering the colour blue, and a selection of the most effective cultivars for displaying this hue. As has been mentioned previously, it is interesting to consider the time of year that your foliage will have the greatest impact in the garden and this colour may be particularly effective in summer when it will be enhanced by the (hopefully!) blue skies we will be enjoying. Floral and Hardy’s Top Five Blue Beauties: Cerinthe major purpurascens Otherwise known as ‘Honeywort’, Cerinthe major purpurascens is an upright annual flowering cultivar which can grow up to 60 centimetres tall and whose foliage will alternate between blue and turquoise throughout spring and summer. The flowers of this plant have bright purple petals, offset by a vivid yellow heart and they will also be accompanied by purple bracts growing at the base of the flowers. They are highly attractive to bees and will thrive if cutting is performed regularly. They prefer well drained soil and a sheltered position that enjoys full sun, but the Honeywort is fairly indifferent to soil structure and will perform equally well in almost any ph. level. Festuca glauca ‘Elijah Blue’ ‘Elijah Blue’ is a compact, clump-forming, evergreen ornamental grass, producing strikingly blue tufts of wiry foliage about 20 centimetres tall, accompanied by blue-green flowers in the summertime that, come autumn, will fade to pale brown. However, these blooms are tiny to the point of unnoticeable and so will not detract from the beauty of the foliage itself. The plant will require very little maintenance and even better is suited to the majority of environments, withstanding high levels of exposure or extremes at either end of the ph. spectrum. Helictotrichon sempervirens If you like the Festuca but need something a bit bigger, the ‘Blue Oat Grass’ might be for you, as this is another dense evergreen with a tufted habit - rather like the Festuca, but taller. Its rigid, spiky leaves will grow to approximately 1.4 metres in height, in a blue or silver tone throughout all seasons. In the summertime it will also produce brown flowers in small spikelets borne on broad panicles, provided it is grown in full sun, however, the eponymous foliage is quite hardy and will therefore thrive in most environments, even in poor soil, but it does prefer an alkaline based soil. They can be easily propagated by means of division following flowering in mid-summer. Hosta ‘Hadspen Blue’ ‘Hadspen Blue’ is a small herbaceous perennial of minimal maintenance that will grow to a maximum height of 35 centimetres m within 2-5 years. It is possessed of smooth, blue-grey, heart-shaped leaves and produces summer blooming, bell-shaped, mauve flowers. It has a clump forming habit and will perform best in heavy clay or loam based soil, however, despite its high level of hardiness, it does prefer a sheltered position and an acidic ph. level, so be aware that a light, sandy soil may cause its leaves to yellow. Hostas are notoriously attractive to slugs and snails, however, they don’t seem to like the blue-leafed varieties as much, so this one might be a good choice. Juniperus squamata 'Blue Star' This is a dwarf, coniferous shrub with bright blue, needle-shaped foliage, forming a dense, low-growing clump. Being an evergreen, it will give good year-round colour, making this a particularly dramatic choice if planted en-masse, which may be necessary as the plant only has a maximum height and spread of 50 centimetres and 1 metre respectively. Another extremely hardy cultivar, Blue star can be planted in any well-drained soil and will even tolerate very hot and sunny sites. However, it is also important to note that all parts of this cultivar are toxic, so maybe not a good choice where there are young children or pets. So concludes our segment on blue foliage, which hopefully will be as much a highlight to your garden as the blue skies they will reflect, come their summer matinees.