It has been a wet, wet wet day. It has not stopped raining all day. But this week it has been fairly bright, with a few fierce showers, and after sunny, frosty weather a week ago it has been cold and windy this week. Although not great weather it has been good for the daffodils. The cool temperatures have meant they have lasted well and some are still going strong. It has not been quite so good for the tulips. Frosty nights will not usually kill tulip blooms but they can make the stems bend and as they thaw the sometimes assume interesting, sinuous stems.
I am pleased to say that these ‘Greenwave’ tulips recovered fully after they thawed but I would not have been too bothered if they had not: wavy stems would be totally appropriate for these spectacular blooms. This page features my two favourite tulips and they could hardly be more different but ‘Greenwave’ reflects the (usually hidden) extrovert side of my nature. Big and very longlasting but with subtle colours this looks good in the garden but really excels as a cut flower. You only need five or six in a vase to make a really spectacular display. It is a parrot sport of ‘Groenland’ and is tall and easy to grow. Just to illustrate this, the photo above is of bulbs planted in autumn 2013 that were cut for flowers in the house, making sure to leave the basal, big leaf intact, and then left in the ground. This year they repeated the performance.
The other part of my personality is reflected in ‘Ballerina’ which is more demure and staid. It is also sweetly scented and bight orange – unlike me. I love this tulip because it has a bright colour which stands out in the garden but has perfect ‘lily flowered tulip’ shape with pointed petals and flaring form when fully open. And like most orange tulips it has a lovely perfume. When I lift these bulbs at the end of the month I will dry them and later plant them in the border with some yellow foliage for next year. I should have been more generous this year with them or have grown more myosotis because the blue pansies are a bit too low to make a good contrast – it works in theory but doesn’t quite in practice.
And so we move on to the last of the three, a bulb that was replanted from last year and is now pulled up. This bloom is attractively striped thanks to virus infection. There are several viruses that cause streaking in tulips but this is probably tulip breaking virus. It typically ‘breaks’ the dark colour of the petals and causes white streaks and feathering but also causes concentration of the pigment in other cells. The patterns can be different on the inner and outer side of the petals. At one time tulips with this patterning were highly valued and they were the basis of great financial speculation in The Netherlands in 1637. Vast sums were invested in bulbs that did not actually exist – sound familiar? – and sums equivalent to ten years wages or more were spent on single bulbs. The trouble is that the virus does not just turn a plain tulip into an amazing one but it also weakens the plant and eventually the bulb dwindles away. So tulip varieties were selected that grew strongly so that they produced beautiful flowers but still retained some vigour when they were infected. the red and white ‘Semper Augustus’ was one of the best known. Because of the debilitating effect of the virus it is no longer legal to sell these infected tulips which are sometimes called Rembrandt tulips. But you may have seen these for sale. These are not really the old kinds but mixes of streaky tulips which have these colours because of genetics, not virus. So if you can’t buy ‘broken’ tulips, where did mine come from?
Well, not having a time machine it had to come form somewhere else. Viruses are odd things and plant viruses have to be moved from one plant to another. It was long ago thought that the phenomenon of colour breaking was caused by ‘rectification’ or the bulb degenerating into a wild form, especially as the bulb then usually dwindled away (Clusius 1576) or that it could be encouraged by planting tulips in poor ground. In fact the latter could lead to it because weak, sickly plants are more prone to aphids – of which more in a minute. But by the days of tulip mania growers knew that it could be spread form one bulb to another by cutting a piece of the infected bulb and placing it on the unaffected bulb. They knew that something was passed on.
Amazingly, it was not until research work at the John Innes Institute in Norwich (UK) in 1928 that the virus responsible was discovered. Tulip breaking virus has only one other host and that is lilies. When you buy lily bulbs they are often (I would say usually) infected with one of more viruses. These usually cause mottling of the flowers and streaking of the leaves though they also cause stunting and sometimes death of the flower buds. The main vector of this and other viruses is aphids, especially Myzus persica. The aphids feed on the lilies and carry the virus from the infected sap on their stylets (piercing mouthparts) when they move on to tulips. Once infected it is not possible to rid the plants of the virus.
It is possible to clean some plants of virus though. Thanks to our ability to grow and propagate plants by ‘micropropagation’ dissecting the tiny growing tip (or other plant parts) in lab conditions, it is possible to ‘clean up’ some plants. So you can buy virus-free strawberries, raspberries and petunias. This is because, in a plant, the virus reproduces slightly slower than the cells at the tip of the plant so the very tiny growing tip is free from the disease and it can be excised and used for propagation. But enough of that, I am supposed to be talking about tulips! Incidentally, most viruses, including this one, are not spread by seed.