Life on Rozanne

September 19, 2011 § 25 Comments

One of the best hardy geraniums is ‘Rozanne’. It has large purple flowers that bloom from early summer until autumn. In a good year, it performs for six months. It is a tremendous sprawler, and isn’t recommended for small gardens. Even though we don’t really have the room, we grow it in several of our borders. We control its conquistadorial tendencies by hacking chunks off the clumps — which is really a form of extreme dead-heading. It looks frightened for a few days, and then it quickly pulls itself together and produces a fresh flush of flowers.

Geranium 'Rozanne'

For years, ‘Rozanne’ was confused with the very similar ‘Jolly Bee’, and only gardeners-in-the-know professed to be able to tell the difference. One was more sprawly than the other. Or maybe not. [Warning: unless you have a burning desire to watch a nomenclatural tangle being unravelled, you might want to skip the next paragraph. But, do click on all the photos in this post: they’re quite interesting. I’ve a novel surprise for you at the end, as well.]

Both are hybrids of G. wallichianum ‘Buxton’s Variety’, with G. himalayense providing the other parent for the first, and G. shikokianum var. yoshiianum for the second. And both are patented plant varieties, which means that they have brought in wads of revenue for the patent holders — Blooms of Bressingham and Dutch breeder Marco Van Noort, respectively. However, in 2010, a court ruled that they were too similar to be distinguishable, and that ‘Jolly Bee’ should cease to exist as a separate variety — bad news for Van Noort, who would no longer receive plant breeder’s royalties. To confuse matters further — and such are the convolutions of plant nomenclature — the original name of ‘Rozanne’ is ‘Gerwat’ (the first appellation under which it was registered) although it is known as Rozanne® in the trade.

The thing that is rarely written about ‘Rozanne’ though (or ‘Jolly Bee’, for that matter), is that it is a complete hit with invertebrates. Honeybees, bumblebees, flies, hoverflies, ants and other small creatures flock to it, to drink its nectar and to pluck the bits of pollen that are tucked into its stamens.

Marmalade hoverfly (Episyrphus balteatus) collecting pollen

The marmalade fly (above) is one of the few hoverflies that actually eats pollen. Before ingesting the grains, it crushes them between its front legs (I nearly said “paws”, as I have a huge affection for this particular species and find it easy to get a little woolly about it).

‘Rozanne’ is sterile, that is, it produces no seed. This characteristic allows it to bloom for a very long period. Normally, a plant’s biological clock tells it to stop flowering when it has made enough seed to perpetuate itself, but a sterile plant has no “stop” for the blooming mechanism. It flowers until colder weather and lower light levels say it’s time — finally — to quit. So, the gooey amber pollen grains that you see stuck to the furry stigma below have fallen on barren ground, as it were.

Pollen grains on 'Rozanne'

I’ve noticed more insect varieties on ‘Rozanne’ than I have on any other plant in my garden. Here is a pretty common carder bumblebee (Bombus pascuorum):

Common carder bumblebee

In my patch (and in many other Irish gardens) it is the most frequent bumblebee visitor. One of its identifying features is its furry, ginger-coloured waistcoat. In sunny weather, the hairs can become bleached, turning it into a blonde bumbo. If you look closely while it is feeding, you’ll see that it has quite a long tongue. It is one of only two bee species that feeds on our native foxglove. The other is the garden bumblebee (Bombus hortorum), which has the longest tongue of any bee in the UK and Ireland: 1.5 to 2 centimetres when at full stretch. It often leaves it extended when it is flying between foxglove blooms, as below:

Bombus hortorum sticks her tongue out at a foxglove

But back to ‘Rozanne’. It is also, as I mentioned earlier, very popular with flies. I’ve seen loads of different species visiting. I’m not sure of this one’s name (if there are any dipterists reading this, please do help), but it didn’t mind standing quietly and having its picture taken:

Fly sunbathing on Geranium 'Rozanne'

Let’s take a closer look at that:

What is THAT?

Yes, the fly is blowing a bubble. Slowly, slowly out and slowly, slowly in. I’m not sure why it does this, but I have read that it may aid food digestion. In any case, it was so focussed on bubble-blowing that it stayed perfectly still while it was having its portrait taken. Isn’t it lovely?

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