MARCH in the garden

March should see your dahlia patch flourishing. There may still be some plants not flowering due to heat or weather conditions in general. If the plant is stunted and there are no flowers you also need to check for disease or contaminated soil. Tuber rot,  virus and contaminated soil all mean you need to discard your plant. Do not try and take cuttings or offer epsom salts to "boost" the plant. This might alter the appearance in the short term but will not fix the plant and you will risk other healthy plants becoming contaminated, particularly with virus.

Stem rot (sclerotinia) is a fungal issue. The stem will get a  section that goes brown and starts to rot. Cut the affected stem away and check inside the stem. You will find little black elliptical pellets about a 3-4 mm long. All affected parts of the branch should be burnt or taken to the dump. The spores from this fungus can be harboured in the petals and soil. Ensure deadheading is kept up to date. Spray the plant with a fungicide including the surrounding soil.

If buds have not appeared or are very slow to grow then you might want to think about removing the buds to enable the plant to put energy down into growing good tubers.

Keep dead heading to prolong your flowering time. In the coming weeks your flowers will get smaller and fewer. This is completely normal. With continual deadheading you will effectively be cutting back the plant. Take any damaged or dead bits out. If you plant is down to a straggly few flowers it is safe to cut the plant back by about a third. If you have used netting to stake then cut back to the top layer of netting. Your next cut back will be to the bottom layer of netting in April/May. You can continue to spray for powery mildew if you want but as autumn takes hold it will become difficult to combat. Don't worry, it is normal at this time of year and wont affect the tubers. If you are unfortunate enough to get a frost in March, it will do the cutting back for you. Simply cut off the blackened damaged stems and leaves, after about 2 weeks. The plant will still be translocating sugars to the tuber at this time.