Our gardening guru delves into his inbox and then sets you some tasks...
Q: Please can you tell me what is wrong with my rhododendron Naomi. The flowers were beautiful but the trouble is the foliage. New shoots are arising from the base. Shall I cut it back to these new shoots? JK Emsworth.
A: It needs a good feed straight away. Fork over the soil lightly and apply five gallons of Maxicrop with sequestrine (you will find it in stock at Keydell in a blue plastic container). After this use a whole bag of ericaceous compost over the area and water afterwards. The top dressing needs to be three inches deep. The leaves will slowly return to a deep green. I would not cut the shrub down to the new shoots just in case the new shoots are the stock on which the plant was grafted.
Q: The dreadful wind has spoiled my beautiful Japanese maple in a large pot. The tips have died back. Do I have to wait until autumn before pruning out the dead parts? GL, Lee-on-the-Solent.
A: Sorry to read about this but very pleased you have put your lovely tree in a sheltered spot. Plant pot wheels are very good aren’t they? Actually this time of year is perfect if you need to prune or reshape Japanese maples. A lot of people don’t know that. Cut back each shoot to one eighth of an inch above each node and use sharp secateurs.
Q: Our apricot has a nasty wound and a deep cavity. It is 35 years old and fruits well every other year. We love it. We are wondering what to do. My friend told me to fill the hole with cement as they used to do that at Kew Gardens years ago. What do you think? FS, East Ashling.
A: Clean the wound on a perfectly dry day and dry the cavity with lots of paper tissues. Use Medo and paint the inside of the cavity. Two hours later mix sawdust and Medo together to make a paste and fill the cavity making sure water can run off the stem. Concrete was used to fill cavities 50 years ago at Kew Gardens but is no longer used as it was found difficult to cut through concrete when a tree had to be felled.
JOBS FOR THE WEEKEND AND BEYOND
•Take three-inch-long cuttings from aubrietia and remove the bottom two inches of leaves. Put them in a 50/50 mix of sharp sand and seed compost. Keep them in the shade and protect the box from cats. They should root in three to four weeks.
•Place greenhouse ferns in a shady part of the greenhouse. Many get scorched leaves if left in direct hot sunshine.
•Feed greenhouse cucumbers by top dressing the compost’s surface with a little Vitax Q4 fertiliser, then water with a rose on the watering can. In a few days, new white roots will appear on the surface. Then, top dress the compost’s surface with John Innes No3 compost to increase the number of fruits. Repeat several times at weekly intervals.
•Summer-prune apple trees. This means cutting the side shoots to half their length. The prunings will be soft and should be composted. This practice will induce fruit buds for next year’s apples.
•Use fingers and thumbs to see if early potatoes are ready. Don’t dig the whole plant. Give it a liquid feed to encourage more tubers.
•Thin grapes again and blow sulphur dust into the centre of the bunches to prevent powdery mildew.
•Check tall flowers in borders, they may need support if you didn’t use hazel sprays in March.
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