Everyone wants plants that grow in the shade and even more want ground-cover plants. Unfortunately there is a common misconception about ground-cover plants: that they miraculously spread over the soil, killing existing weeds, will prevent weeds from appearing and need no maintenance to keep them healthy and attractive. In reality there are no plants that fullfil all this. Some come close in some regards but a garden is dynamic so nothing will rush across the ground and then stop and flourish. Pachysandra is superb ground cover in shade and will last for decades, neat and tidy, but it spreads really slowly. Lamium spreads quickly and has flowers and looks pretty, but it soon gets tired and worn out.
Ajugas are in the same group – they romp across the soil, look great for a year but then the problems start. Most cultivars are of Ajuga reptans, native to the UK and Northern Europe. It is a pretty plant with chunky spikes up to 15cm high, with violet blue flowers. The leaves are green, sometimes with a purple flush. It grows in shade in moist soil. In the garden it will thrive in shade but only if the soil is moist. If it is dry then the plant collapses and gets mildew so your lovely purple or golden foliage looks awful. In fairness, when at its best, these can be really beautiful: ‘Burgundy Glow’ has leaves in grey and cream, flushed with pink and when covered in blue flowers and when strong and vigorous it is a gem.
Keeping then growing is the key with ajugas so divide and replant them every few years, mulch them so they have something new and organic to root into and don’t let them dry out.
Anyway, back in spring I saw an ajuga I didn’t know so had to buy it. I brought it back to Ireland and cut off all the non-flowering shoots to propagate it so I now have a dozen plants. What confused me were the tiny flowers tucked in between the leaves and the compact habit with small, rather hairy leaves. It was ornamental enough, with irregular white splashes on the leaves, and a sprinkling of flowers, but something just looked odd for it to be Ajuga reptans.
So it turns out that this is not Ajuga reptans at all (phew) but A. decumbens, a species from Japan. Like so many interesting new plants, this one comes from Terra Nova in Oregon. The plant patent was published in 2010 and it seems that ‘Sparkler’ was a mutant of an older cultivar called ‘White Mottled’ that happened in the lab – presumably the plant was being ‘micropropped’. Anyway, although ‘Sparkler’ has less variegated leaves than ‘White Mottled’ it is much more vigorous and a better garden plant. Well, that’s what the patent sheet says. On the other hand, more research turns up the story that this is a tetraploid (double the usual chromosomes) form of the Japanese plant ‘Hanabi’ (meaning fireworks), raised by Takuya Izumi and is actually a hybrid of A. decumbens and A. yesoensis that should be called Ajuga x bastarda – very, VERY odd! Even odder is that some sites say its a hybrid of A. decumbens and A. reptans. Who knows? And who cares? Probably not you by now!
Anyway, it is a pretty little plant, ideal for fairy gardens and moist shade and apparently the leaves go pink in winter too.