Thompson & Morgan

Facebook Q&A Session - October 29th


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Name: Tricia Gillan
Question: I have an ice plant (sedum) in my garden to attract butterflies and bees but it is going black, although my neighbour's is fine. It is planted in full sun and against a wall, is there anything I can do to prevent this happening next year if the plant survives?

Answer: Hi Tricia. Sedums are deciduous herbaceous perennials and will die back naturally in late autumn, when the first frosts blacken the stems and foliage. It could be that an early frost has caught your plant if it is in an exposed location. If your neighbours plant receives more shelter then this would explain why their sedum is still doing fine. You just need to cut back the stems to ground level and new buds will emerge next year. However, as we have not yet had much frost this year I would be surprised if this were the cause of your plant turning black.
Take a look at the crown of the plant. If it is wet and slimy then the plant may be suffering from crown rot. This is a common problem in sedums and other succulents which occurs when the plant receives too much water, or when the water supply is too sporadic. Gardening on heavy, poorly drained soil also increases the risk. If the crown feels squidgy then I’m afraid that the damage is already done, and it is best to dig your sedum up and compost it. Next time, before planting a sedum try adding plenty of grit to the soil to improve the drainage.


Name: Lorraine
Question: Hi, we just purchased some Lathyrus plugs from you. Should they be over-wintered indoors / in the greenhouse or can we plant them straight out into the garden before the ground gets too cold?  I've potted them up and popped them in the cold frame for the time being. The garden isn't quite ready for them yet anyway as we're still preparing the soil before the frosts hit hard.

Answer: Hi Lorraine. Sweet peas need a cold but sheltered position over the winter – your cold frame sounds perfect! You could also place them in the greenhouse as long as it’s unheated. (A heated environment would promote soft, leggy growth.) You can plant them out in the spring once the ground has warmed up, although if you’re in the north of the country you may want to delay this until late spring.


Name: Milesandjo Owen-ferrante
Question: How and when is the best time to prune a 1 year old olive tree?

Answer: Olives are very slow growing and require little pruning. The crown of the tree will normally branch naturally so it is best left to its own devices. If you need to prune out any badly placed or frost damaged shoots then leave this until the spring.
As your tree is still quite young I would also suggest that you offer it some winter protection this year. If it is in a container then move it to a frost free greenhouse or cool conservatory. If it must stay outside then cover it with several layers of horticultural fleece during particularly cold periods and wrap some bubble wrap around the pot to prevent the roots from freezing.


Name: Pauline Smith
Question: I have a peach tree that is 1 year old. It fruited at the beginning but all the fruit dropped off after a couple of weeks. It is still healthy but what did i do wrong. It lives in my greenhouse.

Answer: How disappointing, but this may have done you a favour in the long term. Young trees should be limited in their fruit production to allow them to grow and establish a strong framework of branches during the first 3 years.
It is common for many fruit trees to undergo a ‘June drop’ when the tree will shed an excess of fruit. Peaches fruit on one year old wood so I would imagine that your poor little tree was inundated! It is absolutely essential to thin the fruit on your peach tree to allow 15-20cm (6-8”) gap between each fruit along the branch. It may feel as though you are removing most of your crop, but this process will allow each fruit the space to develop properly, and prevent the tree from being weakened by carrying an excessive crop.
Of course, if the fruits were not pollinated in the first place, then they will also drop naturally. This can be a problem in a greenhouse where there a fewer pollinating insects. You can improve pollination by gently tickling each flower with a small paintbrush.
Finally, make sure that there is adequate ventilation on warm days and keep your tree well watered while it is carrying fruit. When fruit trees experience drought they will often shed their crop in order to reduce their water demands. Best of luck next year, Pauline.


Name: Emma Martin
Question: Hi, I have just found you on facebook and have a question for you. I have a small allotment and this is my first year. I had a great crop from potatoes, courgettes, cucumbers, corn and beans but am wondering what I can plant over the winter as I don't want to just leave it unused all winter. I would be greatful of any advice. Thanx x

Answer: Hi Emma. At this time of year there are a few things you can sow to harvest in the spring like Broad Bean ‘Aquadulce’ and Pea ‘Meteor’. Now is also a great time to plant autumn garlic and onion sets for a bumper harvest in early summer next year.
Brassicas are suitable for growing over winter; however you normally plant them in the summer to allow them time to mature before the cold weather arrives. You could consider dedicating an area to perennial fruits and vegetables like asparagus, rhubarb, strawberries, raspberries, and currants, which can all be planted now.


Name: Pamela Howat
Question: Advice please for rejuvenating a border where there was a large Lleylandii hedge. It is cut down but stumps remain. Was thinking about building raised bed and infilling with soil/manure to improve ground and save having to dig out roots. Would this be a suitable as I would then like to grow some dwarf stock fruit trees and vegetables. What sort of depth should I build up or should I bite the bullet and try and remove stumps? Sorry for long question! Thanks

Answer: Ideally you would have the tree stumps ground out by an arboricultural contractor (this would be a lot quicker than digging them out) but a raised bed would also work well and would be perfect for growing flowers and vegetables. 
You need to allow at least 30cm depth of soil over the stumps if you grow flowers and vegetables but I would personally make it 45cm (18”). This will be much easier on your back when you are gardening and will be better for the plants too. Fruit trees are deeper rooting and might struggle after a few years in a limited depth of soil but you could plant currants, raspberries and strawberries. As you’ve already mentioned, you will need to add plenty of organic matter into the bed, mixed with a good quality top soil. Good luck and let us know how you get on.


Name: Pat Hollands
Question: I am growing mushrooms, had them in a cupboard covered with newspaper, can see the little white bits now, what do I do....do you water them on a regular basis....thanks

Answer: Hi Pat. I am assuming that you are growing white cap mushrooms. These can be grown in a mushroom box or bed. The mushroom bed or box should be tightly packed with prepared compost and the spawn scattered across the surface, before covering with damp newspaper. After 3 weeks, the compost will be colonised by mycelium. I’m guessing that you are at this stage now!
You now need to prepare a casing mix. This is mixed from 50% garden soil, 50% peat, and 2 or 3 handfuls of lime per bucket of casing mix. Before you use the casing mix it must be thoroughly wetted and allowed to drain. Remove the newspaper from your mushroom box and cover the compost with a 2.5cm (1”) layer of casing mix. Thereafter keep the compost and casing evenly moist (but not wet) by watering with a fine rose watering can.
Mushrooms will begin to develop 3 to 5 weeks after adding the casing layer. Maintain a moist, humid atmosphere as the mushrooms develop. They will grow in flushes every 10 days or so. You can harvest the mushrooms by simply twisting the cap until it comes away from the compost. We sell a wide range of mushrooms which are now 25% off!


Name: Dinah Marshall
Question: Help what is wrong with my Bay tree the leaves are going yellow and dropping off it is in a pot and has been for five years thankyou.

Answer: Hi Dinah. Oh dear, it does sound like your Bay tree is unhappy. It is natural for evergreens to shed a few leaves in the autumn, however my immediate thought is that it may have outgrown its container as Bay trees have quite extensive root systems. Try re-potting it into a larger container in the spring, using a soil-based compost such as John Innes number 3. If the rootball is compacted then make sure you loosen some of the roots with a garden fork before you repot it.
The yellowing leaves could also signal a lack of nitrogen in the soil, which is essential for healthy leaves. In the spring try feeding your Bay with a well balanced liquid feed, or work some fish, blood and bone into the compost when you re-pot it. You should to continue feeding it once every 2 weeks throughout the summer. One final point, Bay trees are very resilient to drought but will be much happier and healthier if they receive a regular supply of water. This is particularly important during hot dry periods when the soil can dry out surprisingly quickly. Your Bay should be a lot happier with some more space, and a regular supply of water and nutrients!