Thompson & Morgan

Facebook Q&A Session - 01/10/2010

Click here to view details of our previous Q&A sessions.




Name: Chrissy Knight
Question: Can anyone tell me. I had a Tree Peony from you three years ago. It has never bloomed. I feed it and it is in a raised bed. Filled with compost. Any ideas. It has grown to a height of 3ft.....

Answer: This is quite a common question with tree peonies, and there are a number of reasons for flowering to be delayed. A three year old tree peony should be capable of flowering, however it does take them some time to settle in after planting, and some varieties require longer.
It sounds as though your peony is growing well but it’s worth checking the area that you planted them in to ensure they are growing in optimal conditions. Peonies are at their best in sunny positions and won’t do well in heavy shade. They also need shelter from cold drying winds and strong early morning sunlight. Check the soil isn’t too wet as the plant will struggle and eventually rot – peonies like moist soil, but it must be well drained.
You should also check that the tree peony is planted so that the grafted union sits at least 10cm (4”) below the soil surface. Shallow planting may hinder establishment and is often the cause of delayed flowering. Take care not to over feed tree peonies. If you are gardening on a reasonably fertile soil then a high potash feed in spring, and a mulch of well rotted manure or garden compost in autumn will probably be sufficient.
If everything looks as it should, and the plant appears to be healthy then it may just require more time. I’m afraid that these plants are not for the impatient gardener, but they are well worth the wait once they do begin to bloom.

Name: Victoria Lewis
Question: Can anyone tell me what I should do with Gazanias through the winter? I have read conflicting info and there was no information about this when I received them in a T&M lucky dip pack earlier on in the year. Can I also ask the same regarding the Geranium sky rocket that was included in the CFS offer pack? Thanks

Geranium SkyrocketAnswer: Hi Victoria, gazanias can be a bit hit and miss with our winters, which is why they’re grown as annuals. If the winters are mild, gazanias will normally survive, but if we get long cold spells of temperatures below-freezing point then they will almost certainly die (this year’s weather being a prime example!). If you want to keep them then it would be safest to lift the gazanias and replant them in pots for over-wintering. Take as much of the root ball as you can, and gently firm the plant into a pot of multipurpose compost. Water the plants and place them in a bright, cool (but frost-free) greenhouse or conservatory. During winter keep the compost on the dry side to discourage rotting. You can plant them out again after the risk of frost has passed in May next year.

The same applies to the Geranium Skyrocket; move it to a bright, frost-free place. You can also prune back the stems of by up to two-thirds. The secret to over wintering geraniums is to keep the compost almost dry during winter.

Name: Gill Le Fevre
Question: When is it too late to plant bulbs for next spring, and to move/plant shrubs?

Answer: Hi Gill. Most spring bulbs are best planted by October as this gives them a nice long period to form roots before flowering. The exception to this rule is Tulips which are best planted in November. If you plant bulbs after these times they may not perform well next spring.

For shrubs it is normally best to move them during their period of dormancy (Late October – February) although evergreen shrubs are better moved during October or March as the soil is warm enough for roots to grow and establish quickly. For more information on moving shrubs please refer to the Facebook section of our website and click on Sue’s Q&A session for 17/09/2010.

Name: Daphne Cook
Question: How do i take sunflower seeds from this years plant so that I can use them next year?

Answer: Ideally you should leave the heads of the sunflowers on the plant for as long as possible – until they turn brown; although they can be cut when the back of the flower heads turn yellow. This may be a better option if you don’t want the birds to get the seeds first! Cut the heads off along with about 30cm of the stem and hang them upside down somewhere dry like a garage or shed. Wrap a paper bag around the heads or hang them over a tray to catch any seeds that fall. To prevent mould make sure there’s good air circulation. Hope that helps Daphne.

Name: Penny Benjamin
Question: I want to plant an intruder proof hedge at the bottom of my south facing downward sloping garden, I like the idea of roses, should I have a mixture of native hedges, what sort of ratio would I need? It would be right next to my veg patch, so don't want it to make the neighbouring soil too dry or create a frost pocket, any ideas?

Answer: To make a really good intruder proof hedge you need to use prickly shrubs that have a dense growth habit and will form a barrier all year round. Rosa rugosa can make a very prickly hedge but this can also make it really nasty to prune. It is vigorous and fast growing, so many people deal with the pruning issue by simply cutting it back to ground level each year, however this would leave your garden open to intruders. Roses are also quite greedy plants and there is the risk that they might compete with vegetable crops for nutrients.
Personally, I think that there are better alternatives. Hawthorn (Crataegus monogyna) and blackthorn (Prunus spinosa) make lovely prickly barriers of deciduous native hedging, that really knit together with time. Both are also excellent for attracting wildlife, offering spring flowers, autumn berries and excellent nesting cover.
If you would prefer an evergreen hedge you might also consider pyracantha or holly Ilex aquifolium). Pyracantha makes a good thorny barrier, and the flowers and berries provide lots of interest throughout the year, and also attract wildlife. Choose a variety from the ‘Saphyr’ range as these have better resistance to fireblight.
Holly makes a nice formal barrier with time, although it is quite slow to establish and you won’t be able to buy it bareroot which makes it more expensive. If you decide to go for holly, then choose a self fertile variety such as ‘J.C. van Tol’ or pick a female variety and plant just a few males in between to ensure that you get lots of berries.

Name: Wayne Brewin
Question: I have made some Dahlia cuttings this year (August time) and they have grown nicely. The question is, would they have developed tubers by now and if so do I need to lift them and store them or do I keep them in the pots in the greenhouse to grow slowly over the winter months? Many thanks.

Answer: Hi Wayne. As you only started the cuttings in August, it is unlikely that they will have formed tubers yet (maybe very very small ones!). I would keep them in their pots in a frost-free greenhouse this year. Keep the soil on the dry side to discourage rotting. You may notice the growth slows and stops due to decreasing day length and cooler temperatures. Grow them on next summer, and by this time next year they should have formed sizeable tubers. Good luck, let us know how you get on!

Name: Dinah Marshall
Question: What do you do with Calla Lillys when they have gone to seed can you plant the bulb like things thankyou.

Answer: Hi Dinah. It’s best to leave the seed head on the plant until the seed capsules change colour to yellow. They are best sown as soon as they’re ripe. Once the seed capsules become soft you can remove the seeds and sow them about 1cm deep in pots or trays of compost. Keep the compost moist and put them somewhere warm with a temperature between 21-27C. Germination time can vary so don’t be surprised if it takes a few months for them to come through!

Name: Brew Bob
Question:I have strawberry plants in a pot, what sort of autumn/winter care should I provide if any?

Answer: Hi Bob. Your strawberry plants are perfectly hardy and they should be fine if left outdoors. In fact a bit of cold weather will probably do them good! Just clean up and cut away any old foliage and plant debris that has accumulated in order to destroy overwintering pests and diseases. If you can move the pot next to a fence or wall then this will help to shelter the plants from the worst of the weather. The main thing to look out for is that they don’t get too wet. Check that the pots have plenty of drainage holes and that the compost is free draining  to prevent the plants from rotting.

Name: Wayne Brewin
Question: Thank you, but I have another question if it’s ok? I purchased the Begonia Inferno plants from T&M this year and they have been brilliant. I want to keep them for next year and have researched over wintering Begonia’s but cannot find info on these specific ones, ie: whether they have tubers etc? The closest I can find seem to be begonia boliviensis so should I follow the advice on these or could you please tell me how to over winter them?

Begonia InfernoAnswer: Hi Wayne. Begonia inferno are really quite spectacular aren’t they? They are fibrous begonias and it is easiest to buy fresh Begonia inferno plants each year. However, if you have a heated greenhouse then you could bring containers of them indoors for the winter. They will need bright, filtered light and a minimum temperature of 10C (50F). Check for pests and diseases before you bring them in and cut them back by about half. As a safeguard you could try taking some cuttings from the pieces of stem that you have removed, in case the main plant doesn’t survive the winter.
They will probably become dormant during the winter months, so you can reduce watering and keep the compost just moist until they begin growing again next spring. You will need to keep an eye out for botrytis though, as they are quite prone it.

Name: Dan Balyckyi
Question: I bought one of T & M 's collections of oriental lilies and they have been brilliant all summer.They are now forming seedheads, any advice on cultivating these please. Many thanks

Answer: Hi Dan. Growing oriental lilies from seed requires some patience! Wait until the seed heads have turned brown before collecting the seeds. It’s best to sow them straight away into damp compost and cover with a further sprinkling of compost. If you cover the containers with cling film/polythene bags it will help retain moisture. Keep them warm – between 15-21C is a good temperature. Keep them at this temperature for 3 or 4 months then move them to your fridge for at least 3 months.
If any have sprouted after 3 or 4 months, move them into a bright place to grow on, the rest should be put in the fridge. By time they are finished in the fridge, it will be late spring/early summer and the perfect time to place them outside in a cold frame or in the ground. Growth will be small the first year and it may take a few years before plants produce a flower.
Due to hybridisation and complex genetics you may find some of the seed is not viable so don’t be put off if you have poor germination. Good luck!

Name: Julie Pearce
Question: Two questions for Sue. I planted the collection of 3 (jumbo plugs) Syringa in pots earlier this year. Two have got a white residue on the leaves - like a mould or fungus. What should I do?
Also, Any idea why my Polka raspberry canes, now in their second year, are only half the height and producing half the fruit compared to last year? Is it because of the drought conditions earlier in the Summer?

Raspberry PolkaAnswer: Without seeing your plants, I’m guessing that your lilac has powdery mildew. Powdery Mildew affects a wide range of plants and is often associated with humid conditions and the plant becoming dry at the roots. It is unlikely to kill your plants but it will certainly weaken them.
Powdery mildew can be controlled by spraying with a fungicide. There are lots available, just check the manufacturers label to make sure you choose one that is suitable for clearing powdery mildew on ornamentals. Collect up and burn any infected plant material as the plants defoliate to reduce the spread of spores. Also, try to prevent the plants becoming dry at the roots by ensuring that they are adequately watered. Container grown plants are particularly susceptible to powdery mildew because they are reliant on us for their water source. Once they are large enough, you can plant them outdoors where they will be less susceptible.
With regard to your raspberries, Polka is quite a vigorous variety that copes well with less desirable soils. However drought will certainly limit its growth as the plants are quite shallow rooted and can be easily affected. Prune your raspberry canes to ground level in February and apply a thick mulch of well rotted manure along each side of the canes, taking care not to bury them.  This will help to retain moisture at the roots throughout the summer, and also give them a feed at the same time. Hopefully you will have a much better crop next year.

Name: Victoria Lewis
Question: Another one for Sue-I have planted some runners from my strawberries and they have now rooted in the pots. Whereabouts on the runner do I need to cut away from the main plant? Thanks

Answer: This is a fantastic way to increase stock of your favourite strawberry plants. Over time the runners will eventually shrivel and die back by themselves, although you’ll probably want to plant them before then! Cut the runner close to the base of the parent plant and also at the base of the offspring, with clean secateurs. Provided that the baby plants are well rooted, then they should be grow on happily without the need for the parent plant.