Thompson & Morgan Facebook Q&A Session 5th August - Your horticultural questions answered.

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Name: David Leighton

Question: We have a few of your Melon 'Edonis' F1 Hybrid on the go and at the moment we have 3 tennis ball size fruits. The problem is they have been this size for about 3 weeks and have not progressed. We have 2 plants in a grow bag in our unheated greenhouse growing flat and the fruits are on the window sill so not sat on the soil. They are being fed with tomato food. Should we just wait or are we doing something wrong.

Answer: Hi David, this could be a reaction to stress. I’m wondering whether perhaps the long period of cool and overcast weather we had at the end of July could have slowed the growth of your melons. Melons are tropical plants and are happiest growing at a consistent temperature of about 25C. They also need plenty of water to aid the swelling of the fruits. You are doing the right thing in feeding your melons with tomato food as they are very hungry plants - make sure you feed them once a week. Once you have enough fruits on each plant (allow a maximum of 4 or 5) you should pinch out the main growing tip of the plants and the tips of any side shoots, to concentrate the plant’s energy on developing the fruit. I think all you can do at this stage is wait, and hopefully the fruits will start to swell with the warmer spells we have had recently. Good luck David, let us know how you get on.

Name: Louise Rowley-Spendlove

Question: Just harvested 1st bag of Maris Piper potatoes these were bag and spud offer earlier in year so disappointed could hold harvest in one hand 5 tiny spuds :( Have grown in ground on allotment and never had such bad results. Any idea why?? planted after chitting when they had good growth into part filled bag and soil topped up regularly as the plant grew and harvested when top growth had died back.

Answer: Hi Louise, I’m sorry to hear you’ve had such an exceptionally small harvest - it sounds as if you’ve done all the right things. I haven’t harvested my maincrop potatoes in bags yet but it will be interesting to see the results. It is disappointing when the leaves look so full of promise but the harvest is so small! There are several reasons why this may have happened. If your potato plants were given rich growing conditions with lots of nitrogen, this will have encouraged them to put on lots of leafy growth at the expense of forming tubers. On the other hand if the compost you used was old or had previously been used for planting something else, your potato plants may have been lacking in nutrients. When growing potatoes in bags and containers it’s best to feed them every other week with a special potato fertiliser which has the right balance of nutrients for high tuber production. Ordinary multi-purpose compost generally only has enough nutrients to keep a plant happy for 6 weeks. It’s also worth considering how well watered your potatoes were. If you allowed the bags to dry out at any point this would have prevented tuber production. Conversely if the soil was consistently too wet the tubers may have failed to form, or even rotted in the soil. I hope this explains why your harvest was so small Louise - hopefully next year you will have better results. Let us know how you get on.

Name: Shamim 'dizzy' Khan

Question: I have an oleander and it very temperamental. It alive just barely though, no life in it doesn't thrive well, looks wilted all the time. Any ideas please???

Answer: Hi Shamim, it doesn’t sound like your Oleander is very happy! There could be many reasons why your plant is behaving in this way - it could be a cultivation problem, a pest or a disease. Make sure your Oleander is getting plenty of water, particularly in hot weather or if it is being grown against a building where it might receive less rainfall. If the soil is prone to becoming dry (or if it is very heavy clay) it would be best to mulch around the base of the shrub every year with organic matter such as well-rotted manure or compost. This will help improve your soil structure and will provide nutrients for your plant. It may be worth looking closely at your plant and underneath the leaves for symptoms of a pest or disease - such as holes, discoloured areas or distortions/bumps. If you could take a photo of your Oleander and any close-ups of the leaves and stems I may be able to help you further on this.

Name: Karen Simpson

Question: Can you tell me what these are? They just appeared in my garden where I used to have some candelabra primula and at first that's what I thought they were because the young leaves were almost identical but they look very different now they've grown. I left them to grow because they're quite pretty but I don't actually know if they're proper flowers or weeds.

Answer: Hi Karen, this is indeed Borage as the others have suggested! It is a hardy annual herb which bees adore. The flowers look fantastic in drinks and sprinkled over a salad (they are edible). Take a look at our borage seed for more information.

Name: Calum Wiley

Question: I got some tree lilies from your company earlier in the year. I planted them in 5ltr pots to start them off, as my garden was not ready and it was a bit cold. When they began to shoot and it was warming up, I just put the whole pots into the ground as I didn't want to disturb the roots because I had found with other plants the compost was just crumbling away from the roots when I was removing the pots. Anyway, they are no where near 2m high, just about 70cm tall and are about to flower.My questions are, does it take a few years for them to reach 2m, do they need lifted in the autunm and if not, should I take them out of the pots & plant them?

Answer: Hi Calum, you’re right - the tree lilies do take a year or two to reach their full and amazing height! I think you will need to remove the bulbs from their pot as this may restrict future growth. Wait until the autumn when the leaves yellow and die back before lifting. You can lift and store the bulbs this winter ready to plant out again in the spring, or re-plant the bulbs when you lift them. Lily bulbs can be left in the ground for the winter provided the soil doesn’t become waterlogged. Once they are in a permanent position you should start to see an increase in height each year, provided the soil is enriched with manure or compost before planting and then mulched each year thereafter. Make sure you plant the bulbs at 3 times their own depth and 15cm apart for the best performance. Good luck Calum, we’d love to see a photo next year.

Name: Susan Miller

Question: Is it impossible to grow the edible passion flowers versions in the UK??

Answer: Hi Susan it would be difficult to grow the edible Passion Flower (Passiflora edulis) successfully in the UK. This tropical climber originates from Brazil and would need to be grown in a heated greenhouse all year as it doesn’t tolerate frost. Even under cover they may produce a reduced crop if the weather is dull and cool for long periods (as often happens in British summers!).

Name: Paula Grant

Question: How can i stop my clematis leaves turning black?

Answer: Hi Paula. This is a tricky question to answer without a picture or some more information. Have the stems suddenly blackened, wilted or collapsed and died back from the shoots? If so then your plant may possibly be suffering from Clematis wilt. Cut back the infected stems to ground level and burn them or remove them from the site. However I should mention that Clematis wilt causes very sudden, quite specific symptoms so if the stem tips look ok then it is unlikely to be Clematis wilt.

Often the leaves towards the base of the plant will gradually turn brown as the plant sheds its oldest foliage. This is quite normal in mature clematis plants and eventually leaves a clear stem at the base of the plant. Environmental causes can also bring about changes in leaf colour. Sudden hot periods, nutrient deficiencies and soil drought are but a few potential causes. There is also the possibility that your plant leaves are covered in sooty mould. Check the young stems for aphids which excrete a sticky substance onto the foliage. Fungal Sooty moulds often occur as a secondary infection because this sticky excrement offers ideal growing conditions for this fungal disease. I’m sorry that I can’t be more specific Paula - hopefully something here will ring a bell with you!

Name: Trisha Goff

Question: Help rust disease on my young leeks any ideas???

Answer: You are not alone Trish! Rust is a very common fungal problem on leeks causing orange streaks on the foliage with raised pustules containing spores that are easily dispersed on the air. In very severe cases rust can even cause the leaves to yellow and wither, dying back prematurely and stunting growth. Rust attacks tend to be most prevalent from midsummer to autumn and seem to be encouraged by warm humid conditions. There is little that you can do for your current crop but you can still use your leeks - simply cut away the infected areas before you cook them. For future crops here are a few preventative measures that are well worth taking.

Plant hygiene is the key. Destroy any infected plant debris and burn it or remove it from the site - don’t put it in the compost heap. Try to practice crop rotation on your plot and choose rust resistant leek varieties. Increase the spacing between plants and make sure that there is good drainage to improve ventilation and reduce humidity. Avoid using too much high nitrogen fertiliser as nitrate rich soil causes lots of lush growth which is particularly susceptible to rust. Potassium rich fertilisers will help to counter this problem. Finally, keep an eye out for early signs of infection and as soon as they appear. An old exhibitors trick is to smear Vaseline on the infected areas. This will seal the spores in and prevent them from spreading to the rest of your crop. Hope these tips help you Trish.

Name: Derrick Still

Question: Can you please Identify this plant for me ??

Answer: Hi Derrick. This looks like a mutated rose. Mutations are one of those things that sometimes naturally occur in plant genetics. However these mutations can also be brought on by changes in temperature, virus and even insect damage at a cellular level in their earliest stages of flower bud development. If this mutation is caused by bud damage or temperature then the rose will probably produce perfectly normal flowers next year.

Name: Jo Moore

Question: I have a 25 gallon round water tank which I thought I would like to grow a fruit tree in. What would you suggest? The garden is fairly sheltered and very sunny.

Answer: Hi Jo. This is really a question of your particular tastes and preferences, but I would suggest that you choose a tree that is grafted onto a dwarfing rootstock as this will make it better suited to growing in a container. We sell quite a few different patio fruit trees including cherries, peaches, apples, pears and citrus fruits. One other thing to consider is whether that tree will be a self fertile variety - if not then it will need a pollination companion in order for fruit to set. If you are struggling to choose just one tree then try one of our family fruit trees with more than one variety grafted onto them. If you fancy something unusual then perhaps this Quince will fit the bill. It can be grown quite successfully in a container. Whatever you choose you will need to use a soil based compost such as John Innes No. 3 and make sure that you drill plenty of drainage holes into the bottom of the container. Let us know how you get on Jo.