Your gardening questions answered

Guy Barter, Head of Horticultural Advice at the RHS, answers your gardening questions
Plum tree
Plum trees can sometimes attract small insects called lacewings, that are helpful in the garden as an effective predator of greenfly
Question: I picked a plum from my tree and on the plum is a bunch of the tiniest white flowers. Each flower has three petals and there are 11 flowers on numerous stalks. The height of the bunch is 8mm. Can anyone give me some more information and identify what this could be please?
P. Brown, West Yorkshire

Answer: We were nearly foxed here, but our Wisley principal entomologist Andrew Halstead immediately recognised them as the eggs of a 'lacewing', a small insect that is very helpful to gardeners as it is an effective predator of greenfly and other small creatures.

As few plums are likely to be affected, it would be a good idea to put those with these eggs by other plants to help nature control pests in your garden.


Question: I would like some advice about how much to water my new tree. It's a Robinia pseudo-acacia frisia which has been planted in my back garden for around six weeks. The only advice I have found is that young, newly-planted trees require "a lot of water", but how much is alot?

During the warmer weather, I was watering it daily (about half a bucket) but I'm afraid of over-watering. How much water does it need throughout the year until it's old enough to cope on its own?
Corinne

Answer: The amount of water varies from nil in winter when the leaves have fallen, to plenty in the summer - and plenty means enough to keep the rootball and surrounding soil moist.

Start by watering with two watering cans around the tree and leaving for four hours. Then check using your trowel. If the rootball and the nearby soil are still not moist, add another two more cans, and so on, until the soil and rootball are damp. This should keep the tree growing each week in high summer and every two weeks in spring or early autumn, but you will be wise to check every few days.

After a while you ‘get your eye in’ and future planting won’t be such a chore. Once the tree starts growing strongly and you find many roots exploring the surrounding soil, you can stop watering and the tree will ‘stand on its own feet’, which usually occurs within two years.


Question: While a new cable was fitted to a telegraph pole on our property, my rambling rose was ruined. It had been happily growing for the last 20 years and flowering particularly well in the last two years. Having done some research, I believe it may be a rose called 'Seagull'. I would like to buy a new mature specimen to replace the dead rose, but so far I have only been able to find standard specimens. Can you help?
J. Pearson

Roses often regrow after cutting but in this case it has clearly succumbed. Seagull is widely offered and you should have no problem sourcing a plant, but mature examples are not offered as roses tend not to transplant well. The good news is that ramblers grow fast and will soon occupy the available space.

Send your questions for Guy Barter to: gardenproblems@standard.co.uk.

Only a few questions per month can be answered. For further advice on handling problems in your garden, visit www.rhs.org.uk/advice/index.asp.

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