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Facebook Q&A Session 8th March 2013


Thompson & Morgan Facebook Q&A Session 8th March 2013 - Your horticultural questions answered.

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Name: Jennie Callow

Question: How and when do I take cuttings from Daphne plants please?

Answer: Hi Jennie, Daphne cuttings are best taken as semi-ripe cuttings in mid-to-late summer. Prepare your pots first, choosing small 9cm pots or similar. Fill them loosely with a mixture of 50% compost and 50% perlite for good drainage. You can gently firm the compost once with your finger tips but its best not to compact it too much. Semi-ripe cuttings should be taken from the current season’s growth and should have a fairly hard base and a soft top. It’s best to take a heel cutting, where you simply select a healthy young shoot and pull it away from the main stem, leaving a ‘heel’ (a piece of the main stem) attached. Remove the leaves on the lower third of the shoot and cut any remaining big leaves in half to reduce water loss. Dip the heel of the cutting into hormone rooting powder to encourage rooting and protect from rotting. Insert the cuttings around the edge of the pots, spacing them so the leaves aren’t touching. Water well and allow the pots to drain before placing inside a clear plastic bag. Keep the pots somewhere warm and bright but out of direct sunlight if possible. Make sure the compost remains moist. After 6-8 weeks you should start to see roots appearing out of the drainage holes, at which point your Daphne cuttings can be potted on. I hope this helps Jennie, good luck.

Name: Helen Ashby

Question: Any tips for filling raised beds? Is normal top soil ok, or should I mix with compost? Thanks in advance.

Answer: Hi Helen, if your raised beds are permanent it’s a good idea to fill them with top-soil in addition to organic matter such as compost or well-rotted manure. Top-soil will give the growing medium some structure, improving drainage and encouraging good root growth. Organic matter alone (such as compost) breaks down over a number of years to leave a dense growing medium with little nutritional value and poor drainage. We have some hints and tips on creating raised beds and how to obtain topsoil in our 'How to Grow Plants in Raised Beds’ article, which you may find useful. I hope this helps.

Name: Julie Pearce

Question: If you use grit or vermiculite with seed compost, once you have moved the seedlings on (pricked them out) what do most people do with the compost and grit remaining in the seed tray or pot? I usually tip the compost out onto the garden, but reluctant to do so if it has grit on it.

Answer: Hi Julie, that's a very good question. A small amount of grit or vermiculite won’t hurt on your garden borders as they generally contain a large volume of soil. The only time I wouldn’t add grit to the soil is when growing carrots and parsnips as this can cause them to fork or produce stunted roots. Grit and vermiculite won’t break down in the soil but in small quantities will soon incorporate nicely. If you have large amounts to dispose of then this would be ideal for creating an alpine or Mediterranean style border, the plants of which require excellent drainage. If you’re concerned that you have too much leftover grit then you could dispose of it at your local recycling centre as hardcore. I would normally only use grit to cover seeds which take a long time to germinate, such as herbaceous perennials, trees and shrubs. For all other fast-growing seeds I would just use vermiculite. I hope this helps Julie.

Name: Lucy Garden

Question: Hi, Sue, I planted two rhubarb crowns in my raised bed in late autumn, which was probably just as well, given the rest of the garden has had pools of standing water for much of the winter - but when should I expect to see some signs of life? I've not had much success with rhubarb in the past.

Answer: Hi Lucy, it sounds like you’ve planted your rhubarb in the right place! They certainly don’t like water-logging and also resent their crowns being covered with mulch. I plant my rhubarb with the crown just at the soil surface. On wet soils it is recommended to plant with the crown just poking above the soil surface to try and prevent rotting. Normally rhubarb is pretty quick to start growing in the spring and you should see leaves emerging this month, particularly with the warmer days we’ve been experiencing lately. You can take a careful look at the crown now - normally some fat white or pink buds are visible underneath the brown sheaths.

Question: Also - any tips for rejuvenating those areas of the garden (heavy clay) which have turned into ankle-deep mud? (Unfortunately we had to keep walking on some areas.) Some were originally lawn, some were planting areas. Thanks for your help, Sue!

Answer: The best thing to do with heavy clay soil is to keep improving it annually by digging in lots of organic matter such as well-rotted manure, compost or recycled green waste. This is best done in mid to late spring or in autumn when clay soil is at its most workable. It needn’t cost a fortune either. Old multipurpose compost from patio containers will work nicely, plus any homemade compost from your compost heap. Also speak to your local stables or farmers. They will probably be very pleased to get rid of some manure if you are prepared to bag it up yourself - always take the well rotted stuff from the bottom of the heap!

You could also try walking on planks during the winter to help prevent the soil becoming compacted underfoot. Walking on clay soils damages their structure, encouraging water-logging. You may find it beneficial to add some coarse grit to your soil to help open up the structure. Make sure that you dig it in really well to mix it properly. Growing plants in raised beds, as you’ve mentioned with the rhubarb, is a good way to get around heavy clay soil. If you want to try and keep a lawn in these difficult conditions it would benefit from some added grit and organic matter (prior to planting) and regular autumn care including spiking with a garden fork to aid drainage. I hope this helps Lucy, best of luck with both your rhubarb and soil improvement.

Name: Hannah Bufton

Question: I have an old wisteria covering a pergola (lovely) - pruned on time. However it has climbed into a nearby tree (lovely display for the neighbours). Will that decrease the display down below? Should I spoil the neighbours display by cutting down the climbing bit?

Answer: Hi Hannah, ideally Wisteria plants need regular pruning for the best blooming, and if allowed to climb into the tree unchecked, you could find this reduces the number of flowers. Bear in mind that as the wisteria matures and climbs higher into the tree it will become more difficult to manage. If you can access the tree easily and keep this portion of the wisteria well pruned each year then this shouldn’t pose any problems at all - your neighbours will still get a good show and you will also get a fantastic display on your pergola! For more help and guidance on growing wisteria take a look at our Wisteria guide. I hope this helps, good luck.