HELEN YEMM THORNY PROBLEMS

This week: poinsettias on the fiddle, how to kill lavender with kindness, and it might be the end for one old euphorbia

Last Christmas I was given a lovely poinsettia. In March I cut its straggly growth back a bit and it went outside for the summer, where it thrived. I am now tempted to try to get it to turn red again for Christmas – even though I remember you have written in the past that you regard this is a bit of a fiddle. For those of us who enjoy challenges, could you describe the fiddle?

LIZ DICKENSON – VIA EMAIL

A timely email: to re-create the gaudy bracts, the rigmarole starts now.

Bring your poinsettia indoors, remove any yellowing leaves and trim wayward shoots to achieve some sort of symmetry, and don’t forget to clean the outside of its pot (in my experience every pot brought indoors carries at least one gastropod). Every evening put the pot in the darkest part of your cellar, or a cupboard, or simply place a black bin bag over its head to exclude all light for at least 12, preferably 14, hours a night, while maintaining an even temperature.

A couple of weeks before Christmas, give up this palaver and with any luck your plant will have acquired red bracts, resembling one you could have bought for a couple of quid, wrapped in cellophane and tied with ribbon.

As you may have guessed, I am not a fan of this Christmas interloper, and no one will ever persuade me this is worth doing. But good luck.

I have no success with lavender. A healthy plant acquired in spring and planted with great care has gone downhill. Some branches have died, others are losing leaves. Have you any tips?

BRIDGET WATSON – VIA EMAIL

You don’t say anything about the site

TIP OF THE WEEK

or the soil, both of which have will have a lot to do with these failures.

Lavender is a native of the rocky, dry, sunny hills of the Mediterranean, and these are the conditions we should aim to replicate when growing it. In our usually damp, frequently poorly draining and rich garden soil it tends to struggle, and also in “sunny” places that are just not sunny enough for long enough.

We also tend, in our eagerness to get plants off to a good start, to add comforting moisture-retaining organic matter to the soil when we plant, and follow this up with watering and feeding.

If you find yourself ripping out this sorry specimen, do things differently next time: choose the sunniest site possible (it is often tricky to find a fully sunny site that is not too

exposed in our climate) and add a lot of horticultural grit to the soil before you plant to ensure immaculate drainage, plus a very little bonemeal.

Water the planting hole before you plant, rather than water the surface after planting. As you firm your lavender in, ensure that the junction between root and stem does not get buried below soil level. Thereafter don’t feed and water only sparingly.

MIGHTY MITESIn a hot summer plants suchleft, show red spider mite damage, inset left

For those tweakers (rather than lumberjacks) with high hedges or shrubs to neaten or tree canopies to thin out: try the lightweight Darlac Snapper, with secateur blades that hold light prunings in their grasp (rather than dropping them on one’s head). There are shorter fixed-length and telescopic versions. See demo on darlac.com.