Thompson & Morgan Facebook Q&A Session 18th March - Your horticultural questions answered.

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Name: Lynda Radcliffe

Question: When is the best time to prune a Tree Peony as mine is growing lop-sided?

Answer: Hi Lynda. Tree peonies generally respond quite well to pruning, which is best under taken in late winter or early spring, just as the buds begin to swell - so now is the ideal time!If your tree peony was planted in the last two years then you should really only take out the occasional dead stems while the plant is still establishing. Cut stems back to a live bud or to just above ground level.

However if the plant is already well established but somewhat misshapen, then you can prune each stem back hard to about 15cm (6") from ground level to encourage new stems to be produced. However, it is important that hard pruning should be spread over a number of years, pruning back just one main stem per year. After several years your tree peony should have developed a better shaped framework of stems. Of course, this process will risk the loss of some flowers but the end result will be worth the sacrifice!

Name: Zoe Hindmarch

Question: I have a question, what's the best way of ridding the lawn of dandelions? They drive me crazy. Thanks, Zoe

Answer: Hi Zoe, dandelions are hard to kill as they have a deep taproot and they self-seed prolifically. If you have the time or if there are not too many dandelions, then digging them up by hand is very effective. Alternatively you could use a lawn weed killer which will specifically kill broad-leaved weeds such as dandelions but will have no effect on the grass. Specific lawn weed killers are available in all good garden centres. Once you have eliminated the weeds it is also worth giving your lawn a high nitrogen feed in the spring to keep it in good health and vigour, reducing the risk of weeds taking a hold. The healthier the lawn, the less likely weed seeds will be able to germinate and grow.

Name: Anna Mason

Question: One for Friday I think - I Have Dianthus Strawberry parfait in a container from last year, very bedraggled. If I dig out and chop top off and plant a bit deeper in a pot will it grow ok and can i take cuttings of shoots ??

Answer: Hi Anna. Dianthus chinensis ‘Strawberry Parfait’ is a short lived perennial or biennial so it is unlikely to grow back with any vigour, which is why it is usually sold as an annual. Given that you really have nothing to lose, I think that it is definitely worth a try!

Repot it into fresh, free draining compost but take care not to bury the lowest leaves. Trim back the worst of the foliage and place it in a sheltered position such as a greenhouse or cold frame, to protect it from wet weather. Water sparingly until the plant has fully rooted into its new pot. If your Dianthus does regrow then you should take cuttings from non flowering shoots this summer. Best of luck, Anna. Let us know how you get on!

Name: Kevin Joseph

Question: Question for sue. Hi sue I’m back about my camellia, by the time you next have your Q&A the camellia would have finished flowering and i know that is the time to prune it. BUT how do i prune it? is it just a case of cutting back to a leaf node? And also how far down should i cut as i would like flowers next march also. If i do cut it hard how quickly will it reach back to the height it is now? Thank you

Answer: Hi Kevin, Thanks for the picture. It always useful to be able to see what you are talking about!

You are quite right - now is the time to prune your Camellia, as soon as the flowers fade. I remember when you asked about this plant in December, you were concerned because the growth was rather spindly and I gave you some tips on rejuvenating the plant through hard pruning. But now that I have seen a picture, I would suggest that it is actually quite a good shape and I don’t think that drastic pruning will be necessary.

I have taken the liberty of annotating your photo to show you what I would do. Remove any dead growth first, and then trim each stem back to a healthy outward facing bud to shape the plant and remove the faded blooms. Reduce the long stems at the top of the plant too. This should promote plenty of new growth, making the plant bushier and increasing the chances of more flowers next spring, as Camellias only flower on new growth.

After pruning provide a mulch of organic matter around the base of the plant, but don’t mound it up around the stem. Remember to keep your plant well watered throughout the summer using rain water instead of tap water (as the lime contained in tap water will reduce the acidity in the soil over time). I hope this helps Kevin. Keep us posted on your progress.

Name: Anna Mason

Question: Another Friday one methinks - I have a rather splendid Tree Peony you sent me.Can I grow her in a container if so what size thank you. Oops its Hong Xia. She arrived as sticks in a bag in Mid Jan. (Please excuse my rude description.)

Answer: It looks like your tree peony is getting off to a flying start! Tree peonies can successfully be grown in containers although eventually after 5 or 6 years they will need planting out into a garden bed. Choose a container that is at least 30cm deep and 30cm in diameter and use soil based compost such as John Innes No.3.

Peonies like good drainage so it is worth mixing some grit into the compost. You will need to top-dress the container each spring with fresh compost and feed you tree peony during the growing season to ensure abundant flowers and strong growth. Try using a slow-release fertiliser to save the hassle of liquid-feeding every few weeks. Lastly, make sure the compost is kept moist, especially during long hot spells.

Name: Matthew Eddy

Question: I have bought hollyhock, lupin, larkspur, foxgloves, delphinuim, 10 week stock, runner beans and tomato seeds from you and they have germinated and the true leaves have appeared but how do I pot them on to grow stronger to plant out. Any tips and help please.

Answer: Hi Matthew. It’s best to prick out seedlings into module trays to allow them to grow on. To prick out your seedlings, carefully loosen the compost around their roots with a dibber or the blunt end of a pen or pencil. Hold the true leaves between finger and thumb and lift the seedlings individually from their tray. Avoid holding the seedlings by the stem as this can easily damage the plant. Use your dibber to make a hole in the new compost and place the seedling inside, lightly firming it in with your fingers or the dibber. When you have finished make sure you water the module tray with a fine-rose watering can to avoid damaging or dislodging the seedlings. As runner beans and tomatoes are quite large plants and will need to be kept indoors for a longer period, I would pot them up individually into 9cm pots to allow for good root growth. For future reference it is best to sow runner beans at the end of April or throughout May because they are so fast growing! They will easily catch up with earlier sowings.

Your hollyhocks, lupins, larkspur, foxgloves, delphiniums and stocks are hardy plants and can be hardened off in April or May when the weather has become warmer, before planting out into their final positions. To harden off the young plants, simply put them out during the day and bring them under cover at night for at least a week. If the risk of a late frost threatens then it is worth covering these young plants with some fleece.

Your runner beans and tomatoes are tender and will need to stay under cover until all risk of frost has passed. I hope this helps Matthew, if you’d like more information about growing seeds take a look at our seed sowing guides.

Name: Lorraine

Question: Hi, I've got a question I was hoping Sue might be able to answer - we bought 3 jumbo Echinacea plugs from T&M in the autumn. I planted them well before winter hit but haven't seen any sign of them yet. When should I start seeing signs of them coming up if they survived? Many thanks!

Answer: Hi Lorraine, I would expect your Echinacea’s to have emerged by late April. Temperatures are still fairly cool at the moment but once we get some more consistently warm temperatures and more sunshine, even the slowest perennials should emerge! Keep an eye out for slugs and put protection measures in place around your Echinaceas as slugs love to eat the fresh new shoots.

Name: Lee Nicholson

Question: Planted 3 maiden fruit trees only a week ago. Think they've established themselves but with a forecast of -1 tonight, do I need to protect with fleece???

Answer: Hi Lee, don’t worry; there is no need to protect your fruit trees as they are fully hardy. As the trees are planted, the young roots will be protected from frost by the soil.