I’VE a mixed bag of problems to talk about this week, all sent in by Examiner readers.
Ann Nicholas from Lepton wrote to me recently about two key gardening issues. Streptocarpus are one of those groups of house plants that either do extremely well or fade before your eyes.
Unfortunately, Ann’s plants have fallen into the latter group recently and she has reached the point of desperation.
I suspect the plants may have a collection of micro-beasties attacking them, either from below or above soil level but possibly both.
Vine weevil grubs can attack below soil level and cause growth reduction or total collapse. Mealy bug infestations, often at the bases of leaves, are common these days and they will reduce the overall vigour of the plants over time.
However, I think the most likely cause is an almost microscopic pest called the Tarsonemid mite that feeds throughout the year on foliage, causing distortion and stunting of growth.
There are no chemicals available to kill off this pest currently and good hygiene seems to be the best solution, disposing of infected plants as they are seen. Biological controls can be used and Amblyseius spp. seem to the best.
Check this parasitic wasp out through www.defenders.co.uk or www.ladybirdplantcare.co.uk .
Ann’s second question is about camellias that did not flower this year and have yellowing leaves.
The two critical factors with camellias is that they have an acid soil (pH6 or below) and that their roots are not allowed to dry out in summer, as this is when next year’s flower buds are forming.
The yellowing foliage may well be caused by a high pH in the soil or compost and the plants would benefit from a fertiliser suited to acid loving plants (without calcium in it).
Gerry Ruttle, an ex-student of mine from my years at Huddersfield Technical College, is having problems getting rooted penstemon cuttings to get established.
Cuttings taken in late summer of soft-wood, non-flowering growth need to be kept in a frost free environment throughout the winter in the best light conditions to ensure a vigorous plant by springtime.
The cuttings should be repotted in March to encourage new roots as the plants start to regrow and these can be planted out, like summer bedding plants from the end of May.
The alternative is to keep a mother plant in a frost-free glasshouse over winter and to take cuttings of the new spring growth as it appears in March and April, just as you might do with fuchsias, dahlias and tuberous begonias.
Mrs Harrison from Kirkheaton is struggling to get any apples on an apple tree that she brought from a car boot sale three years ago.
The label indicated that the tree is a Cox’s Orange Pippin but there is no information about which rootstock the tree is grafted onto – this is essential so that you know how vigorous the tree is going to be.
Cox’s Orange Pippin is a commercial variety that is not really suited to growing in the north unless it is given a very sheltered position, preferably on a south or south west wall, trained as an espalier, fan or cordon to restrict its growth and protect the flowers from frost damage.
The other factor is that it may not have a suitable pollinator close by. According to the RHS listings, this apple is in flowering group three out of seven and you will need to have another cultivar from groups two, three or four to help ensure good pollination, always assuming that bumble and honey bees are around to do the work for you.
If you have any questions or queries that you want help with or gardening related subjects that you would like to discuss, why not write to me at Graham’s Gardening Questions, Features Department, Huddersfield Daily Examiner, Pennine Business Park, Longbow Close, Bradley Road, Huddersfield, HD2 1GQ.