Peter Gibbs is at RHS Rosemoor where he is joined by panellists Bunny Guinness, Matthew Wilson and Bob Flowerdew. We take practical tips while out and about in the grounds and find out how putting some extra work in during autumn can save you time next season.
Produced by Howard Shannon
A Somethin' Else production for BBC Radio 4.
This week's questions:
Q. North Devon is famous for the Victorian Fern craze. Can the team make some "ferntastic" plant suggestions for 2014?
A. There are so many different times of fern, but the Hart's Tongue is very popular. Polystichum provide a good ground cover and require hardly any maintenance. Shuttlecock ferns are fantastic, offering lime-green foliage that unfurls in the spring.
Q. Is it true that runners should be cut out of roses because they take strength from the plant?
A. Gardeners did used to be told to cut off the suckers, but nowadays they are less of a problem as the root stocks have been changed. If you plant them with the root stock well below the ground then you shouldn't have any problems with suckers. If one does appear, it is best to pull it off as you will get the root stock on top rather than the plant you have bought. However, if the foliage looks similar to the rest of the plant it could actually be a basal stem.
Q. What would the panel suggest planting in a small flowerbed that faces northeast and has dry, clay soil conditions?
A. The first thing to do is to improve the soil. Spend about a year applying organic matter in layers to the surface and allow it to break down. Plants such as Japanese Anemone, Bergenias and Polystichums may do well. Bulbs could also work as they are woodland plants and are used to dappled shade. Most of them will flower early when some of the moisture from the winter still remains.
Cannas such as canna iridiflora often don't need as much water as people think and can withstand a lot of shade. These could be framed by a pattern of topiary box for a structure throughout the winter.
Q. Why would butternut squash planted on compost heaps start to split?
A. This is caused by an irregular water supply. The heap must have been moist enough for them to start growing but then there will have been a dry period. This will have caused the skin to harden and when more water arrived they will have expanded and split.
Q. How can one grow Wild Foxgloves and Welsh Yellow Poppies from seed without scattering them naturally?
A. They could be developed as plug plants. If you sow them now they should come up over the winter months ready for planting in spring.
Q. Is it possible to graft a New Zealand Taylor's Gold Pear Tree from a seed?
A. You could have the Taylor's Gold grafted from bud wood, but a pip may not be successful. There are other varieties available in the UK that turn a yellow colour, such as Souvenir du Congris or Doyenne du Comice.
Q. Which plant does the panel think will become the new invasive weed of the twenty-first century?
A. It's not necessarily a case of how easily a plant spreads that is the problem but how hard it is to remove. It also depends on the area and climate. Many woodlands are being invaded by Lamium. It could also be oil seed rape because it is escaping from fields could cross breed. There are nearly twenty plants that have been marked as potential threats.
Q. What would be the best recipe for a free materials compost when growing tomatoes?
A. Each garden differs because ingredients such as manure will vary in nitrogen content. But if you were to add manure to a clay soil along with something such as wood ash you will get an excellent crop. You can add seaweed as a tonic and leaf mould will add structure. Alternatively, a bag of well rotted-down grass turf will also do the job.