Thompson & Morgan
Facebook Q&A Session 8th August 2014

Thompson & Morgan Facebook Q&A Session 8th August 2014
- Your horticultural questions answered.

Our horticultural expert Sue Sanderson runs a fortnightly question and answer session - so if there is something that has been eluding you in your garden, post your question on our facebook page and she will get back to you during her next Q&A session.

View the answers to our previous sessions.

  • Jane Wade Was Jones
  • I want to 'refurbish' a border in my garden, about 4 ms long by 1m wide, it has a path on one side and lawn on the other. I have a wish list of plants but wonder how to go about the process of clearing and the best time to do it.

  • Sue - T&M Horticultural Expert
    Sue Sanderson - T & M Horticulturalist
  • Hi Jane. Refurbishing borders is always exciting, although you don’t mention what is growing there at the moment. If it is full of weed then I would suggest that you spray it off with a glyphosate based weedkiller to ensure that you have a clean border to start with. This can be done now, as it may take a few weeks for a systemic herbicide to take full effect. It won’t be a problem on the path side of the border, but you may need a friend to hold a board as a screen along the grass side of the border while you are working. This will prevent spray from damaging your grass. Of course, if you are an organic gardener then you may prefer to remove unwanted vegetation by hand.

    If there are any plants in the border that you want to save, then these should be lifted beforehand with as large a rootball as possible. Pot them up or move them to a new position in the garden. Once the weeds have died back then you can begin to improve the soil. Clear any remaining vegetation before thoroughly digging over the soil and incorporating plenty of well rotted manure, mushroom compost or garden compost. Leave the soil to settle for a few weeks before you start replanting.

    Personally I would delay planting until the Autumn. The soil will be moist and the conditions cooler, which will be better for plant establishment and save you an awful lot of time watering. Just beforehand you might also want to add a sprinkling of slow release fertiliser or blood, fish and bone to get your plants off to a good start.

    I recently made a video on How to plant a perennial border. Why not take a look for some extra planting advice. Best of luck with it Jane.

  • Sue - T&M Horticultural Expert
    Sue Sanderson - T & M Horticulturalist
  • Hi Bryn. Wireworm can be a real nuisance and there are no quick fixes I’m afraid. The eggs are laid in early summer below the soil surface and once hatched; the larvae will feed on plant roots, potato tubers etc. The bad news is that this larval stage can last for up to 4 years! Eventually they will pupate and the adults overwinter in the soil before emerging in early summer to mate.

    There are no chemicals currently available for use against Agriotes spp. However, the problem should be quickly reduced in soils that are regularly cultivated. Thoroughly turn the soil in autumn and dig it over again in spring. This will expose wireworms to predators such as birds. It is well worth encouraging birds in your garden all year round as they will definitely help to limit this pest.

    While the weather is warm I would also suggest that you apply some nematodes of Heterorhabditis megadis. There are a number of suppliers online. They can be watered into the soil and will kill any wireworms that they find. Given that wireworm lifecycles are so long then it will probably be necessary to make a number of applications over several years.

    If you make your own compost then its worth checking to see whether there are wireworm present. If so, then dispose of the compost off site. Don’t be tempted to spread it anywhere in the garden.

    It goes without saying that it is best not to grow susceptible crops such as potatoes in infested soil. You could try to reduce the damage to any current crops by lifting them early, but this will obviously reduce your potential yields. It’s a difficult problem to control. I hope that you are able to limit it successfully.

  • Claire Cheskin
  • I am going to try to grow rainbow eucalyptus as bonsai, do they need any special food or temperatures?

  • Sue - T&M Horticultural Expert
    Sue Sanderson - T & M Horticulturalist
  • Hello Claire. This is quite a specialist question - and I am certainly not a Bonsai expert (although it is an absolutely fascinating science!). However, I can tell you that Eucalyptus is not a particularly easy Bonsai as it is such a fast growing tree by nature. Don’t try to make it too small - I would suggest that you aim for a height of around 3ft. You will need to keep on top of the new growth as it will be produced rapidly and will need lots of pinching out.

    You will need to use a fairly light sandy soil mixed with plenty of organic matter, and it will require frequent watering, especially during root establishment. Once it is established then a monthly feed with a balanced Bonsai fertiliser will be appreciated. It will enjoy a sunny position outdoors during the summer months. Rainbow Eucalyptus is not frost hardy so it will need to be brought into a frost free greenhouse or conservatory during the colder months of the year. Avoid putting it into a warm room indoors though as this will produce weak, spindly growth.

    There are some superb Bonsai nurseries in the UK who I’m certain would be able to give you more specific information about how to grow these fabulous trees. Best of luck with it, Claire.

  • Irminka Rowe
  • Hi, I have 3 trees growing in my garden, the one on the right is going brown. Is it dying? Also what is the name of the tree on the left? I love it.

  • Sue - T&M Horticultural Expert
    Sue Sanderson - T & M Horticulturalist
  • Hi Irminka. It’s really hard to say as the photo is not particularly clear. The tree on the left could be Cornus controversa ‘Variegata’ but I really cannot be sure without a better image.

    Regarding the conifer on the right of your picture, there are a number of possible causes of brown patches like these. The tree may well be suffering from a pest such as Cypress Aphid or scale. There are also a number of diseases that might be affecting the tree but without more information and a better picture then it is impossible to say. There is also the possibility that it is suffering from some kind of stress - drought, drying winds etc. It would be worth inspecting the tree and it’s growing conditions more closely for any other symptoms that might be present.

    In some instances, bare patches may eventually fill in as healthier branches continue to grow but this can take many years. Don’t be tempted to cut branches back to older, bare wood as conifers cannot recover from this. I’m sorry that I can’t be more specific for you, Irminka.

  • Andy Brown
  • In our school gardens we created a Pumpkin Patch. Went away for 2 weeks holiday and now it's more like a Pumpkin explosion. The plants are huge with runners going very where. Any advice on how to look after these monster plants? Should we cut them back or limit the number of Pumpkins to 1 per plant for example?

  • Sue - T&M Horticultural Expert
    Sue Sanderson - T & M Horticulturalist
  • Hi Andy. Yes they do travel! Pumpkins will begin to produce long stems which can be trained in a circle around the plant to prevent them spreading too far. There’s no need to limit the fruits unless you are planning to grow giant pumpkins!

    You will need to feed and water your pumpkins regularly. When growing pumpkins, a thick mulch of organic matter spread around the plants will help to conserve moisture at the roots. If possible, hoe between the plants regularly to prevent weeds from establishing.

    Leave the pumpkins on the plant for as long as possible until the skin has hardened and the fruits start to crack near to the stem. You will need to harvest the pumpkins before the first frosts by cutting each fruit from the stem leaving several inches of the stem attached. Take a look at this article for more information on growing Pumpkins.