Geranium Rozanne (‘Gerwat’) has become so popular that it is almost a cliche. Few plants are as useful and so certain to delight. We all know that hardy geraniums are reliable, tough and bloom for ages. Of course this is a wild generalisation and some are picky, some only have one fling with flowers and some are liable to become weeds. But in a genus of more than 400 species and hundreds of cultivars there are bound to be saints and sinners.
‘Rozanne’ is definitely a saint, though just a bit smug given all the accolades showered on it. It is a ‘go to’ plant where you need something that will look after itself and just delight you with nonstop flowers of lovely blue. Some geraniums look a bit tawdry by late summer and can be renewed with a haircut. But ‘Rozanne’ doesn’t suffer in this way and just goes on churning out blooms. On the flat it grows to about 25cm high but if there is something to lean against it will throw its limbs higher. Voted ‘Plant of the Century’, it is a great plant.
Lots of claims are made for it and, unusually, most are true. It is even a good perennial for a pot and remarkably grows well in a hanging basket, provided it is well fed and watered. It is almost perfect. I had decided that I would divide my plants and put them under my short row of Hydrangea paniculata for a two-plant combo that didn’t need much work.
But I was looking at how big it was getting and I am having second thoughts. She is big girl. One of mine, planted next to a young parrotia for the perfect autumn combination, is close to smothering it. I will leave all alone and trim the geranium until the shrub can fight back for itself. It is great to cover the ground, or to spill over paving but she is not the sort you want to be sitting next to you on a Ryanair flight – all thighs and elbows!
Now there is a possible rival to Rozanne called ‘Azure Rush’. This is a sport of Rozanne, that occurred in Germany and was introduced in 2007. It is already popular and is rather similar but the flowers are paler and the plant is shorter-jointed so it is much more compact. Despite the allusion to azure, the flowers have a distinct lilac flush. I must say that I am very impressed that a commercial grower managed to spot a compact shoot on a clump of Rozanne and that it was not simply swamped into oblivion.
The two are so similar that I doubt that you really need both when there are so many other lovely geraniums to grow. If you are short on space ‘Azure Rush’ is definitely the better choice. You would hardly know the flowers are paler unless you have them side-by-side and it flowers just as long.
To compare the photos above, ‘Rozanne’ was planted this spring from a divided plant and is almost 1m across, and still growing. ‘Azure Rush’ was planted this spring from a potted plant and is 45cm across. They are in the same bed, in full sun, in rather poor soil.