Thompson & Morgan Facebook Q&A; Session 16th May 2014
- Your horticultural questions answered.

Hi Andy. Don’t worry, it really doesn’t matter. It just makes harvesting them a bit more exciting - sort of a ‘potato lucky dip’! Your potatoes will let you know when they are ready to be harvested. Once they have flowered you will notice that the foliage will start to turn yellow and eventually die back. This indicates that your potatoes are ready to be harvested.

Hello Fall. The bacteria that you are referring to is called Agrobacterium tumefaciens. It causes crown galls on trees. It’s a long time since I tinkered with plant DNA at college and I am by no means an expert in genetic engineering, which is a very complex subject. However, I can confirm that this bacteria has DNA transmission properties which have been largely exploited in delivering foreign genes into plants. It’s a fascinating process, and there is plenty of reading to be found on the subject if you are interested and enjoy reading scientific papers!

Hi Emma. There’s a lot of truth in some of these old phrases. I believe the saying goes, "Ne’er cast a clout till May be out", with May being in reference to Hawthorn flowers. They are certainly in full bloom here so if you are getting too hot in the garden then I’m sure you could risk taking off your jacket now!

In terms of your plants, you can start to harden the larger ones off now but keep an eye on the weather in case we get a cold snap. Obviously this is a greater risk the further north that you live, so if you are on a particularly cold or exposed site then give it another couple of weeks just to be sure.

Hi Steve. Here is a link to the original study. This sort of study is always interesting as it lends scientific weight to methods that have been tinkered with by gardeners for years.

As I understand it, spraying your plants with aspirin is intended to be a preventative measure rather than curative. Salicylic acid which naturally occurs in plants has been indicated to trigger the plants natural defences. Aspirin (acetyl salicylic acid) is a derivative which appears to induce similar effects.

I would anticipate that the dilution of the aspirin and the timing of application are fairly crucial however. Also the effectiveness is likely to be variable depending on the incidence of blight at the time - in wet summers when the disease is prevalent I am doubtful that this method alone would be sufficient to stave off blight. It would be an interesting plant trial for a willing gardener - perhaps you could conduct your own experiment Steve? I’d be fascinated to hear the results.

Hi Clare. It looks like a Tamarix (or Tamarisk as it is commonly called). It makes a very pretty large shrub or small tree, and is particularly useful for coastal sites as it withstands salt laden winds well. Unfortunately we don’t sell it but a quick Google search should find you a supplier online.

Hello Marj. It’s really impossible to give you a definitive answer without seeing the plant. Try taking a look further down the stem to check whether there has been some damage - slugs and snails can often cause damage to the base of young stems at this time of the year and the first obvious signs are often when the buds begin to wilt. Alternatively it may be a disease such as Clematis wilt which tends to hit plants just before the buds open. Are there any other symptoms? If you have a picture and a bit more information then I certainly try to give you a more complete answer.