Eric Robson and the team tackle questions from the audience at this year's GQT Summer Party, held at Ness Botanic Gardens, South Wirral.
In addition there's highlights from the all-day gardening event with appearances from Bob Flowerdew, Christine Walkden, Matthew Biggs, Anne Swithinbank and Pippa Greenwood.
Produced by Howard Shannon and Robert Abel
A Somethin' Else Production for BBC Radio 4
Questions answered in the programme:
Q. A large number of slugs are travelling up an oak tree in my garden. Why do they go up the tree at night?
A. They may be eating the algae or mildew on the oak tree, or may be being drawn towards any rotting parts.
Q. Our 30-year-old magnolia is currently in leaf and bud. Should we be concerned?
A. The season has been so odd that lots of trees and shrubs are flowering out of season. It should be fine.
Q. Could the panel suggest activities to be carried out in our 12ft by 10ft primary school greenhouse?
A. Fill with interesting plants and declare it a spider sanctuary and observatory. Alternatively, carnivorous plants are very interesting to children. Teach them to grow their own vegetables/flowers from seed, or grow plants that have explosive parts; such as ecballium elaterium, or impatiens gladulifera.
Q. Do you have any advice for 'open garden' virgins?
A. The county organiser will be able to give you support, as will other 'open gardeners' in the area.
Q. I would like to grow garlic. The soil is sandy and the garden north-facing. What is going wrong?
A. The crop likes sun and warmth, so should probably be grown in a south-facing garden. Autumn-planting cloves tend to give a bigger bulb than spring-planting.
Q. Why do my onions fall over?
A. Onion growth habit changes as day length increases. Late-planted onions will not make many leaves and mature small, but early-planted onions make more leaves and grow larger. If it is hard to grow them early, start them on ridges or in trays and then plant them out with a root ball.
Q. I love ornamental grasses, but suffer from grass pollen allergy. Can the panel suggest other plants to give a similar effect in a planting scheme?
A. Ornamental sweetcorns will give the height and the slender growth, or verbena bonariensis. Alternatively, you could use grasses that you can cut the flower off. Festuca glauca will not produce much pollen, or you could plant low growing grasses like Coix lacryma-jobi for the grass effect.
Q. My husband and I disagree over my habit of planting vigorous climbers up trees. Is there any room for compromise?
A. The problem with vigorous climbers is that species such as Paul's Himalayan musk, white wisteria or Kiftsgate rose are each capable of covering around 1/4 acre.
Q. Could the new lawnmower with docking charger replace my husband and his ride-on mower, and would both the lawn and my husband benefit?
A. It depends on how large the width of cut is. Over a large area, it may not be practical.