Thompson & Morgan Facebook Q&A Session 22nd July - Your horticultural questions answered.

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Name: Kate James

Question: My Solanum muricatum has lots of fruit, almost tennis ball size. The fruits do not bear any stripes, when do I know when they are ready to pick?

Answer: Hi Kate, it’s great to hear you’ve got a good crop from these unusual tropical plants. The fruits become a creamy-yellow colour when ripe and should develop the characteristic purple striping. The fruits are quite slow to develop and can take a month or two to grow and ripen. Once they have developed the striping you can always experiment with one of the fruits to test if they are ripe. The fruits should yield slightly to gentle pressure and when you cut one open it should have orange-yellow flesh with a similar texture and taste to a melon. Good luck Kate, we’d love to see a photo of your Pepino plants!

Name: Veronika Perry

Question: Hi there, I was wondering if you have any tips what I can do to my huge pear tree. I planted few years ago and now it over hangs the fence over my neighbours side, and all the pears are dangling about 1 foot over his glass greenhouse! Do I cut down the tree or can you advise as it has a lot of baby pears on most of the branches. I think this year all the bees have helped and with all the rain, it has grown very quickly. Thank you.

Answer: Hi Veronika. Apart from the obvious risk of the greenhouse being damaged if the mature fruits drop through the glass; the tree is probably blocking a lot of light from the greenhouse too. I think you need to discuss this with your neighbour to warn him of the problem. Try to gain his permission to remove the pears overhanging his greenhouse. Perhaps you could invite him to harvest them himself and let him keep the fruits.

If it is possible to prune out the offending branches this winter then this would be advisable to prevent the problem recurring next year. However if there are too many branches overhanging the greenhouse then you may need to consider removing it. It would be a great shame as your Pear is obviously doing well, but it is really not worth falling out with your neighbour over a fruit tree. You can always replant another pear tree  somewhere more appropriate in your garden to replace it.

Name: Denys Dyachuk

Question: Our bay leaves tree got ill. I don't know what can be done to get rid of it. Could you advise me please? Thanks

Answer: Hi Denys, thank you for the excellent photos! It looks like you have Bay Suckers, which are sap-sucking insects active in the summer months. The symptoms are yellowing leaf margins which become thickened and curled. Often only one half of the leaf is affected with the yellowed areas eventually turning brown and drying up. Greyish-white insects (the young nymphs) are often seen underneath or near the curled up areas of the leaf (demonstrated in the bottom right-hand picture of the photos you provided).

If the attack is light you can remove the affected leaves and dispose of them with the household waste (don’t compost them). Any badly affected shoots can be pruned out in the winter as this may get rid of some of the over-wintering adults. If the infestation is heavy you may want to try an insecticide spray such as ‘Provado Ultimate Bug Killer’ which contains the active ingredient ‘Thiacloprid’. Do check the spray is suitable for use on edible crops if you use your bay tree as an edible herb and read the instructions on the bottle carefully. Around May next year, check your plant for damage and spray at the first sign of any Bay Suckers - hopefully this will keep your tree healthy for the rest of the summer! Good luck Denys, let us know how you get on.

Name: Carol Burton

Question: My peach tree had lots of blossom this year, but some of the leaves at the tips of the branches seemed to get blisters on them, shriveled up and dropped off. We had 6 peaches on it and two of them had a hole where the stalk is and there were signs of a pest having been inside. Could this have been codling moth damage. Forgot to say the tree is in a large pot.

Answer: Hi Carol. I’m afraid that the symptoms that you are describing refer to two separate problems. The blistered leaves and branch die-back that you describe are classic indicators of the fungal infection Peach Leaf Curl. Once the symptoms of peach leaf curl are spotted in spring it becomes very difficult to treat the problem, so most treatments for peach leaf curl are preventative rather than curative. The fungal spores of peach leaf curl require moisture to germinate, so this infection occurs particularly during wet spring weather.

You will need to spray your peach this autumn and again in February with a copper based fungicide. I would suggest that you follow up your February spray with a second application about 2 weeks later. If your peach is wall trained then you can erect an open ended screen to cover the tree from late winter to May to keep the rain off, thereby preventing the spores from germinating. I know this sounds a bit extreme but this technique has been proven to be very successful.

It’s hard to say what has caused the holes in your peaches - codling moths do affect other fruits but are predominantly a pest of Apples so this is an unlikely culprit. There are lots of potential pests that will cause holes in fruits including wasps and birds. Pest damage is very common in fruits but you should be able to still use the peaches if you cut out the damaged portions.

Name: Ellie Bromilow

Question: Hi Thompson & Morgan, when it was last windy we lost 2 trees which fell over. Is there any you would recommend to replace them? I would like something evergreen (as most trees here drop their leaves in winter) thats not too big but also something that can stand a bit of wind as we are a bit exposed on a hill. (The trees that blew down were a Poplar and the other was a lovely one that had white flowers on it). Do I need to wait a long time before replanting? my OH is going to dig the stumps out with a digger. Thanks

Answer: Hi Ellie, you shouldn’t need to wait to plant another tree although you should feed the soil first, as the old trees will have depleted the soil of nutrients. Before planting, incorporate plenty of organic matter such as well-rotted manure, compost or recycled green waste (available from the local council recycling centres). In subsequent years it will be a good idea to mulch your new trees annually (with manure or compost) to keep improving the soil.

The best evergreen trees for exposed sites are conifers, including Chamaecyparis (which comes in all sorts of colours and forms), Cryptomeria japonica ‘Elegans’ (a very neat conifer with attractive foliage), Junipers and Pine trees. Good smaller Pine specimens include Pinus densiflora ‘Umbraculifera’, Pinus monophylla (Single-leaf Pinon), Pinus sylvestris ‘Watereri’ and Picea pungens ‘Hoopsii’ (which has attractive blue/white foliage). You could also try Yew which is very tolerant of harsh growing conditions. Magnolia grandiflora ‘Little Gem’ is a nice compact evergreen tree and Photinia x fraseri ‘Red Robin’ has stunning red foliage on new growth. Although Cherry Laurel (Prunus laurocerasus) is normally used for hedging, it makes a good dense tree or large shrub too. It’s worth looking around for different varieties and cultivars of the species mentioned as you may find a colour or size which you feel suits your garden best. I hope this gives you a few ideas to start with Ellie.

Name: Ellie Bromilow

Question: Are there any evergreen fruit trees?

Answer: Hi Ellie, unfortunately there aren’t any evergreen fruit trees that will survive outdoors in the UK, although if you have a heated greenhouse or conservatory you can grow a small citrus tree. Olive trees are evergreen and reasonably hardy although may not survive the extreme weather we’ve had in the last few winters. They need a sunny position, preferably near a south-facing wall. Evergreen fruit trees include Mangoes, Papaya and Guavas, which all originate from tropical and sub-tropical areas so unfortunately won’t tolerate cool growing conditions.

Name: Be Jal

Question: Purchased zinnia zahara double mix from you this year and for the first time in my life I have managed to get zinnias to flower. they normally just wilt and die. this orange flower produced some white petals. would it be worth trying to save the seed to see if any of the seedlings produce white flowers?

Answer: That’s great news! I’m glad that you have finally had success with your Zinnias. The mutation in your photo is just one of those things that sometimes naturally occur in plant genetics. However these mutations can be brought on by changes in temperature, virus and even insect damage at a cellular level in their earliest stages of development. Given that it is only one flower that is affected then this is the most likely explanation. It is highly unlikely that saved seed will produce further mutations next year but don’t let that put you off. Saving seed can be a fun learning experience.

Name: Be Jal

Question: Hi t&m or any1 else do you know what this plant is? noticed it today for the first time and dont know how it got there.it is about 4 foot tall.

Answer: Hi Be Jal, this does look like Lamium album (White Deadnettle) although I’ve not heard of them reaching 4ft tall before! They are found in woodland, wildflower areas and on road verges. If it is Lamium album then it is often considered a weed as it spreads very easily by seed and via its creeping rhizomes. The flowers are very good for bees, although it can quickly swamp out other plants so if you wish to keep it do keep an eye on its spread. I hope this helps Be Jal.

Name: Christina Goozee

Question: Found lots of little red spots on my Lotus, Black Eyed Suzy, (Got cobwebbs) Yucka, Gloriosa etc All in conservatory Have sprayed with Provado Whats best ?

Answer: Hi Christina. Sounds like red spider mite to me. This is a common glasshouse and conservatory pest at this time of year, and it is a particularly difficult pest to eradicate. Spraying with Provado should help but spider mite readily develops tolerance to chemical controls and generally requires several applications in order to eradicate all stages of the lifecycle (mites, nymphs and eggs).

Biological controls such as the predatory mite Phytoseiulus persimilis are the most effective control against spider mite. This particular predator reproduces at twice the rate of spider mite. It is highly active under hot dry conditions, where just one mite of P. persimilis can consume 20 eggs or 5 adults per day! However, it requires a minimum temperature of over 16C (although daytime temperatures of 21 C are preferable) and there needs to be sufficient numbers of spider mite present for the predatory mites to feed on. Obviously, if you choose to use biological control then you can’t use chemical control as well because this will kill the predatory mites!

There are a number of cultural practices that you can also use to help prevent and reduce outbreaks. Spider mite thrives in warm dry conditions, so you can try misting your plants to increase the humidity. Regular inspection of the undersides of leaves will also help to detect the problem before it spreads. Pick off and burn any infested leaves when you find them. Finally, at the end of the growing season, make sure that you take time to really clean out your conservatory properly as spider mites like to spend the winter hidden in dry crevices and plant debris until the weather warms up again in spring.

Name: Anna Mason

Question: Does this look like pigeon damage please I was blaming snails but now I wonder ? We do have collared doves and pigeons around.

Answer: Hi Anna. This could certainly be pigeon damage as they tend to strip the foliage from the stalks. Try netting your plants to keep the pigeons off. You can also try bird scare humming line or hang some old cd’s around the plot to scare them. If all else fails, invest in a cat!

Name: Anna Mason

Question: What generally is a good yield from potato bags please?

Answer: That’s a tricky question to answer, Anna. It will depend on the variety and the growing conditions, and can often vary from year to year. But to generalise, a reasonable yield from 5 small tubers (salad or new potatoes), grown in a 40 litre bag might be in the region of 2.5 - 3kg. For a really good yield you might get up to 5kg.

If you are growing larger tubered varieties such as Maris Piper then you might get a larger crop if they are grown in the ground as this would provide more space for the tubers to develop.

Name: Anna Mason

Question: Could someone advise on watering solutions I have a raised deep bed made from gravel boards about 12 inches deep set in a border - so my question is if I recycled some litre plastic milk containers cut base off and buried them at intervals would it be a more efficient system than watering from a can I was thinking a bit like burying a pot in a tomato bucket? Hope it makes sense.

Answer: Drip irrigation systems are one of the most efficient irrigation methods in raised beds and borders, but if you are trying to save on expense then you can certainly try the method that you described. Plunging old 2 litre fizzy drinks bottles or milk cartons into the ground is an ideal method for targeting water to large individual plants such as tomatoes. However if you are planning to fill this bed with bedding plants or rows of vegetables then you may be better off using a leaky hose or drip system.

Name: Sue Hellard

Question: Hi I bought several packs of the egret orchids, most of which have grown leaves but seem to have stopped growing at all now, do i need to feed them, how can I encourage them to flower.

Answer: Hi Sue. Egret Orchids are lovely little plants but they can be a little tricky. Take care not to over pot them to prevent them from rotting. Pot them up in groups of 3 tubers per 11cm pot and use specialist terrestrial orchid compost as this will be very free draining. The tubers should be planted at approximately 2.5cm (1") deep so that the growing point (a small dark eye at one end), is facing upwards.

Grow them in a bright position on a windowsill or in a cool greenhouse but make sure that they are protected from strong sunlight at all times as they are prone to scorching. You can water them freely at this time of the year so long as they are in a really free draining compost. Feed them a balanced liquid fertiliser once a month too - it is best to dilute it to half strength.

The secret with these plants is to understand that they are an alpine species which require a cold, dry dormancy period from autumn to spring. Decrease watering in the autumn as the foliage dies back. Place tubers in a cool position (0°-5°C) for the winter and keep the compost barely moist until the new shoots appear the following spring. In late spring, when the first shoots appear, you can increase watering again and begin to feed them monthly as before. Best of luck Sue.