Q and A's

Questions and Answers

Each month our expert gardening team receive many questions from members of the free Flower Power Gardening Club. Here we share some of the most frequently asked and interesting questions.

Browse through the questions below or trying searching for something specific. If you can’t find what you are looking for why not join our free Gardening Club and ask our expert panel!

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Found 35 questions
  • Question Can you tell me the best way to remove, hopefully permanently, mushrooms from our lawn? They are all over the lawn. Answer

    Mushrooms and toadstools are nature’s natural recyclers. They break down organic matter in the soil and turn it into humus and other materials essential for a healthy soil. Yours are no different and may even be feeding on dead tree roots under the lawn.

    There isn’t much you can do to get rid of them permanently. You should certainly try and remove them with a stiff broom or similar before the caps open and release their spores, spreading them further. Watering on a solution of iron sulphate – 1oz in 1 gallon per 1 square yard – may help control or reduce them.

  • Question Do you have any suggestions as to how to stop squirrels from digging into my patio planters and making a real mess? Answer

    This is a very common problem with squirrels. The best way to deter them getting at bulbs in pots is to use small mesh chicken wire. You can either put this over the top and outside of the pot or, better still, bury it horizontally in the pot about 2.5cm (1in) down and 2.5-5cm (1-2in) above the bulbs.

  • Question I have put a mobile pond in the garden and wondered if I could put a water lily in it but without its roots in any soil? Answer

    The best way to plant a water lily in any pond or water feature is to use a water plant/water lily basket. As the plants will be sold in one of these, all you have to do is carefully lower it into the water! The best time to plant is when it warms up in spring.

  • Question Over the last few months, I have had molehills in the lawn. What can I do? Answer

    Moles can ruin a lawn – trapping them is the only really reliable method – but you must set the traps correctly. Handle the trap with gloves (the moles must not get a whiff of human scent) and don’t put the trap in the molehill. Instead, find the run between two molehills with a metal pole or similar and put the trap there, covering around it with turf making sure that no light whatsoever will get into the run. You can buy humane traps that trap, rather than kill them, if you prefer.

    Some people swear by putting mothballs or similar strongly scented materials in the run, or using one of the battery-operated scarers – or even a child’s windmill – as moles hate vibrations. But these don’t always work. Another option is to try and flood the run with water – but you need to do more than just pour water down the run. Other people swear by using human male (female won’t work) urine poured into the run. Again it’s the smell that deters them.

  • Question I have two Gardenia jasminoides plants – my second lot – and I am having the same problems as the first lot. They were beautiful when I purchased them with loads of flowers and buds. Now the leaves are turning brown and the buds are falling off. What am I doing wrong? Answer

    Don’t feel too guilty or disappointed with yourself, as this is pretty typical of gardenias. They are not the easiest plants to look after – and even more difficult to keep from year to year and get to re-flower. Gardenias need a minimum night temperature of 15-18C (60-65F), 21-24C (70-75F) in the day time. They like good, overall light but not direct sunlight – a shaded conservatory is the best place for them.

    They need very careful watering, aiming to keep the compost evenly moist and only slightly drying out between watering. Always use tepid water that is lime free (not ‘hard’); if your tap water is hard, then you will need to use de-ionised water. Finally, they like a humid atmosphere, so stand the pots in saucers of damp Hortag/hydroleca/gravel and mist the foliage daily.

  • Question I planted my spring-flowering bulbs in autumn as normal, but many of them have already produced a lot of foliage. What can I do to protect them? Answer

    There’s nothing to worry about, since the vast majority of spring-flowering bulbs are as tough as old boots – but far more attractive! The bulbs were fooled into thinking that spring came early by the mild weather we had last autumn.

    If the weather turns very severe – days on end of below freezing temperatures – you could put some horticultural fleece over them and/or some bark mulch around them to provide some cold protection, but usually this isn’t necessary.

  • Question I have just bought a Pernettya mucronata 'Mulberry Wine'. Am I right in thinking that it will need a male plant to cross pollinate to get flowers and berries? As I’m planting it in a container, is ordinary compost okay for these plants? Answer

    Yes, you’re right, most pernettya plants (now re-named Gaultheria mucronata) are either male or female and you will need a male partner for the females to produce berries – it doesn’t affect their flowering. You should be able to buy a male at any good garden centre. There aren’t any varieties as such, they will just be labelled “male”. As these plants are lime haters, you will need to use an ericaceous compost. Also, they prefer shade, so don’t expose them to full, burning sunlight.

  • Question I purchased some houseplants called Gloxinia, which grew a little, but now they are all dying and there are a lots of little flies in them. I have done exactly what it said and stood them on a dish of pebbles and have watered from below. Answer

    From the description it sounds like they have been overwatered. The presence of ‘little flies’ (which are called sciarid flies) does point towards this. Standing the pots on a dish of damp pebbles is the correct thing to do – as this improves humidity around the leaves as the water evaporates. However, the level of water in the dish must not reach the bottom of the pot, otherwise this keeps the compost constantly soggy/waterlogged leading to the roots rotting.

  • Question I have a French lavender, which is quite old and woody. Unfortunately it has been damaged in the strong winds. Is there any way I can save it? Answer

    Once lavenders become old and woody, they lose much of their vigour and regenerative powers. If there is no or very little growth below where it has been damaged, then there is very little chance of it re-growing or, if it does, it will only produce small, insignificant amounts of growth. Prune it back by all means, but it may not come back to its former glory. It would be far better to replace it with a new plant – but leave planting until temperatures warm up in spring.

  • Question Please could you tell me when is the best time to move rose bushes. Answer

    Roses – particularly very old plants – don’t always transplant/move very well, so only attempt it if you really have to. The best time is when they are dormant and have dropped their leaves, so any time from late autumn until the end of February.

    Before moving them, thoroughly water the soil the day before and cut back all the stems by around half to two-thirds. Then dig up as much of the roots as possible with their surrounding soil. Roses, don’t form a rootball as such, so this can be difficult – and one of the reasons why roses don’t transplant too well.

    Re-plant at the original depth in well-prepared soil with lots of added organic matter, and water in well. You will probably have to water thoroughly during spring and summer during periods of dry weather.

  • Question My lily bulbs in pots didn’t flower well this year and I think I should repot them. When can I do this? Answer

    You can repot lily bulbs any time when they are dormant – usually from late autumn (once all the stems have died own) until the end of February.

    You will probably find that the bulbs have produced a lot of small bulbs (called bulbils) around their circumference. These are too small to flower and take several years to reach flowering size. These are best carefully pulled off, potted up into small pots (or several in larger pots) and grown on until they are big enough to flower and then planted out into new pots or into the garden border.

  • Question I have just received two miniature indoor roses. How do I care for them and will I be able to plant them outside? Answer

    Miniature roses are just small bush roses, and so should be treated in the same way as any hybrid tea or floribunda rose. The vast majority are as hardy, so are best grown outside. If you intend to keep them indoors over winter, then keep them as cool as possible – a hot room will mean they drop their flowers early – and water them enough to just keep the compost moist. Only feed with a liquid fertiliser, such as Flower Power, when they are in flower.

    To be honest, it would be best to plant them immediately outside – either in the ground or in containers. If you keep them inside over winter, you will have to slowly harden them off – acclimatising them to outdoor conditions over 10 to 14 days – and then plant out in spring.

  • Question How do I look after poinsettias over winter? Answer

    Poinsettias need a position in good light – but out of strong, burning direct sunlight and a constant temperature of around 15-21C (60-70F). Avoid draughts and chills, especially at night so move plants away from windowsills, but keep them away from sources of excessive warmth, such as open fires or radiators.

    The compost should be kept moist, allowing the top to slightly dry out between watering and, as with all houseplants, always use tepid water – not cold water straight from the tap. Feed weekly to fortnightly with a liquid houseplant feed or Flower Power while they’re in flower/bract colour.

  • Question How do I look after my indoor amaryllis after the flowers finish? Answer

    The time after the flowers of indoor amaryllis (varieties of Hippeastrum) start to die is the most important, if you want the bulb to flower again next year. When the flowers have faded, remove them and the developing seedpods behind them. Leave the flower stem in place, until it starts to go brown and die, then cut it down to the crown of the plant – where it joins the leaves.

    Continue watering when necessary to keep the compost moist and feed fortnightly with a liquid feed, such as Flower Power, while the leaves are still green. If and when they start to go yellow and die back, stop feeding, reduce watering and then stop watering when they die. Keep the bulb in its pot in a cool, dry place (don’t water it) and wait until autumn when it will start to grow again. Then start watering and feeding again.

    If the leaves don’t turn yellow, continue watering and feeding, placing the plant outside in a cool, slightly shady spot in summer. In autumn, cut off all the leaves to 2.5cm (1in) above the bulb and stop watering/feeding. Start again when new growth appears. Amaryllis prefer to be kept potbound, so only repot when they physically start to break the pot!

  • Question I always read that mulches should be applied in spring. But we’ve just planted up a new border and want to mulch it now. Can we? Answer

    This is one of those strange pieces of common advice – with no real science or reason behind it! Certainly you should never mulch when the soil is frozen, nor when it is dry – you should always mulch the soil when it is moist. So, yes, you can mulch now. Just make sure you apply the mulch thickly enough – it needs to be a minimum of 5cm (2in) deep, ideally 7.5cm (3in) deep. If you put it on any thinner, it won’t provide any of its benefits: keeping weeds down; helping to maintain soil moisture levels in spring and summer; and insulating the roots from frost and excess heat.

  • Question What do I do with my dahlias over winter? Answer

    Wait until the first frosts have blackened the foliage, and then it’s time to decide what to do.

    Some people, especially those living in milder areas, take the risk of leaving the tubers in the ground, covering the soil around them with a 15-20cm (4-6in) thick protective layer of straw, compost or bark chips. But to be on the safe side, it’s a good idea to lift the tubers.

    Start by cutting down the stems to 10-15cm (4-6in) from soil level. Then carefully lift the tubers with a garden fork without damaging them. Clear away as much of the adhering soil as possible and then stand the tubers upside down in a dry, airy, frost-free place for a few days to allow excess moisture to drain from the stems.

    Then pack the tubers in boxes or crates filled with just-moist compost, coir, sand or similar material. Make sure the packing material is kept clear of the crown (where the stems join the tuber) or rots may set in. Keep them in a frost-free, cool place over winter, and check them regularly to ensure they don’t dry out or rot.

    Question from Andrea Rose.
  • Question My garden is full of fallen leaves from my trees. It seems a shame to throw them away, so what can I do with them? Answer

    You should certainly clear them away from underlying plants and from the lawn as they can cause dieback.

    Some leaves can be added to the compost heap in small amounts. Shredding those on the lawn first, by going over them with the lawnmower, will help them break down quicker – and it’s easier than raking them up!

    Otherwise, they can be used to make leafmould – an invaluable material that is the perfect soil improver and mulch. Collect up the leaves and put them in a sack or plastic bag, such as a bin liner or old compost bag. Moisten them if they’re dry to help them rot, tie the top of the bag, make a couple of holes in the bottom of the plastic bags and then leave them somewhere for a year or two to rot down. Hey presto – leafmould!

    Question from Dick Burke.
  • Question What are the best shrubs for growing in pots? I like colour in the summer and then maybe something that will give green leaves in winter. And what size pots would I need? Answer

    Just about any shrub can be grown in a container – providing the container is large/deep enough and you use a good compost. So the sky’s the limit!

    We all have our own personal favourites, but if we had to choose 10 good shrubs to give colour from spring to autumn – and beyond – then we would go for: Abelia grandiflora; Buddleia (especially the dwarf Jazz varieties); Hebe; Hydrangea; Lavandula (lavender); Mahonia; Rhododendron (needs ericaceous compost); Hybrid tea or David Austin rose; Rosmarinus (rosemary); Viburnum x bodnantense ‘Dawn’.

    Shrubs should be planted individually in containers measuring around 38-60cm (15-24inches) in diameter.

    Question from Lynne George.
  • Question How can I protect plants growing in containers on the patio from frost? Answer

    The roots of plants growing in containers don’t have the cold and frost protection provided when they’re growing in the soil, and even otherwise hardy plants may become damaged during severe winters.

    Protect the containers by wrapping them in bubble wrap, hessian or, better still, ‘duvets’ made from plastic bags filled with shredded newspaper, polystyrene chips, roofing insulation or similar materials. If possible, move the containers against a sheltered wall or close to a building to provide extra protection. Raise the containers onto pot feet or bricks to avoid them sitting in the wet, which can lead to root rotting and cracking of terracotta pots.

    Question from Laura Atkinson.
  • Question What can I do to give some winter protection to both hardy fuchsias and penstemons kept outside? Answer

    Although these are referred to as ‘hardy’ fuchsias, they’re not totally hardy – they’re just “hardier” than bedding fuchsias! Penstemons are not totally hardy either.

    First, don’t cut down the old stems until spring, as these can provide some protection and ensure the growth buds further down the stems are not damaged.

    As it’s important that the roots don’t freeze, protect them by covering the soil around the plants with a 10-12.5cm (4-5in) deep layer of mulching material, such as bark chips or compost.

    In extremely severe winters, you may need to protect them by covering with horticultural fleece. Stuffing straw or other insulation material around the branches first will provide extra insulation. Then cover with bubblewrap to keep it dry and provide more shielding.

    Question from Laura Atkinson.
  • Question How can I deal with worm casts appearing all over the lawn? Answer

    While worm casts on lawns can appear at any time of year, they are always worse in autumn. Certainly don’t squash them, as they create an uneven surface and provide a perfect seed bed for weed seeds to germinate.

    You can brush away the casts once they have dried, which is not always easy in a wet autumn!

    As casting worms don’t like acidic soil, making it more acidic causes them to go deeper into the soil – where they can’t cast – without coming to any harm – or go to another part of the garden. Regular feeding with a lawn fertiliser such as Lawn Magic should go some way to make it acidic, or you can apply Sulphurlawn

    Question from Mary Askwith.
  • Question I need to move a small shrub that I’ve planted in the wrong place, when is the best time to do it? Answer

    October is the perfect month for moving deciduous small and young trees and shrubs. Wait until it has dropped all its leaves, which signals that it is dormant and safe to move.

    Water the soil around the plant thoroughly the day before moving to make sure the roots are fully charged with water. Where possible, prune back up to half of the top growth, to reduce the stress of moving on the roots.

    Dig up as big a rootball as possible and replant in well-prepared soil with lots of added bulky organic matter plus bonemeal. Make sure the rootball sits at the same level as it was originally. Tall shrubs and trees will need staking to keep the roots secure while they re-establish. Water in thoroughly and keep the soil moist for the first year.

    Question from Albert Robertson.
  • Question Do you have any advice on how to overwinter geraniums (pelargoniums)? Answer

    Pelargoniums, like all half-hardy/tender bedding plants, need to be overwintered frost free (around 4-6C/39-43F) in a light, airy place – preferably a cool greenhouse or conservatory.

    Dig up the plants keeping as much of the rootball as possible. Remove all damaged/dead/dying leaves, stems and flowers and loose soil/compost and cut back the stems by around half to keep them compact and bushy. Then pot them up individually in pots just big enough for the rootball plus a bit of extra compost that you can squeeze between the rootball and the pot with your fingers.

    They don’t need a lot of water over winter, but don’t allow the compost to completely dry out.

    Question from Jeff Nash.
  • Question How do I deal with begonia tubers after they’ve finished flowering? Answer

    You should wait until the growth stops and the leaves start to turn yellow. Then stop watering and feeding and allow the plants to dry out. The leaves and stems will all turn yellow and you can carefully “snap” them off from the tuber. Do this gently to test whether they’re ready to come away – if they are, they’ll part from the tuber with hardly any force.

    Then lift the tubers and carefully remove any soil/compost adhering to them.

    They then need to be stored frost free over winter. You can either pack them in shallow trays of just moist sand (keep the top of the tuber just uncovered) or hang them in nets or stockings/tights. The former method has the advantage of stopping the tubers from drying out – although you have to make sure the sand is kept just moist, but not too wet as this can lead to the tuber rotting. The latter method has the advantage of it being easier to stop them rotting, but you have to make sure they aren’t kept too hot or they can shrivel up, dry out and die.

    Question from Linda Clough.
  • Question When I lifted my lily bulbs, I found loads of little bulbs in a big cluster. Do I split them off, or replant when they are dried out in the spring? Answer

    Lilies produce baby bulbs -– or bulbils as they are called – and this is how they reproduce and are propagated. I would carefully split them off individually, then pot them up straight away in small pots of compost and grow them on, as they can take two to three years to reach flowering size. Then, you’ll have lots of new lilies!

    Question from Neil Roberts.
  • Question I’ve had problems with vine weevil grubs in my containers this year. Is there anything I can do at this time of year to control them? Answer

    Actually, September is one of the best times of year to apply the biological control Nemasys Vine Weevil Killer, which is based on nematodes, to control and kill vine weevil grubs. This is available from several mail order suppliers, such as Green Gardenerw or Pippa Greenwood

    Vine weevil grubs eat the roots of numerous plants, but those in containers are particularly susceptible, as are begonias, fuchsias, heucheras, sedums and succulents.

    Question from Jean Fredericks.
  • Question Should I cut back the stems of my herbaceous perennials? Answer

    That depends! The majority of summer-flowering perennials are unlikely to flower again, so as soon as the flowers fade, you can cut them right back to ground level.

    If you deadhead and cut back the flower stems of some late-flowering perennials – such as asters, chrysanthemums, penstemons and phlox – you may encourage some further late autumn flowers.

    Those perennials with seed heads that look attractive and ornamental right into winter – such as ornamental grasses, eryngium, poppies and rudbeckia – can be left to provide some interest and structure to the garden over winter.

    Many seed heads are also useful food sources for birds, and several beneficial insects, including ladybirds, may take shelter in them during the colder months.

    Question from Adrian Thompson.
  • Question I’ve been given some daffodil and tulip bulbs. Should I plant them now or later? Answer

    The best month to plant all spring-flowering bulbs is September, but you can leave it until October or even as late as November if necessary or as the situation dictates – providing the soil isn’t frozen or waterlogged.

    Most bulb experts now agree that even tulips, which were always traditionally planted in November, should now be planted earlier too. So, you can plant all your spring-flowering bulbs in one go.

    They look great in any part of the garden and can also be grown in containers

    Question from Linda Seymour.
  • Question Can you tell me when to deadhead hydrangeas? Answer

    The best time to deadhead mophead and lacecap hydrangeas is in spring (late March/April), as the overwintering faded flower heads are supposed to give some frost protection to the flower buds nestling just below at the top of the stems. Although we’re a bit dubious that a flimsy flower head can give much protection! Simply cut off the faded flower stem, be very careful that you don’t cut into the main stem, as you’ll be cutting off the flower buds.

    Question from June Hay.
  • Question Is now a good time to prune bush hybrid tea and floribunda roses? Answer

    The main, hard, formative pruning of roses is done in late February or early March. Providing they have finished flowering – and they can flower all the way into winter – you can cut them back by around half now if you want to.
    As roses are generally shallow rooted, the roots can become loose in the soil if buffeted by strong winds. Reducing their height will help prevent this wind rock and so prevent damage to the roots – but this is usually only necessary in windy situations.

    It will also remove some of the overwintering spores of fungal diseases, such as blackspot, powdery mildew and rust, and so help reduce infection next year. Don’t forget to rake up and dispose of affected leaves too to remove sources of disease re-infection.

    Question from Terry Askwith.
  • Question My dog wees on the lawn and, as you know, this burns the grass. Are there any remedies for this problem? I have tried the Australian rocks that are added to the dog’s water bowl. Answer

    The simplest solution is to stop your dog doing it in the first place! A friend of mine has trained his dog to wee down the drain! Maybe you could train it to go somewhere else in the garden away form the lawn.
    Some people say they have solved the problem by adding tomato juice to their food, as this may neutralise the nitrogen-containing compounds in the urine that cause the burning; it is more likely it just dilutes the food. Always check with a vet before making changes to your dog’s diet.
    Always make sure your dog has access to plenty of fresh water, as the more it drinks, the more dilute the urine will be, reducing the problem. And canned food has a lot more water in it than dried food.
    And whenever it does use the lawn as its toilet, make sure you flush the urine deeper down into the soil by applying at least 9-13.5 litres (2-3 gallons) of water to the spot where it has been.

  • Question For years I have tried to grow lily of the valley, but in vain. I have spent more money than I care to think about, growing them in pots and in the garden. All I get are a couple of leaves then nothing. Answer

    You are not alone! Lily of the valley is one of those plants that can be difficult to get established initially – and then when it is, it goes mad and grows everywhere!
    It tends to prefer a relatively poor soil, so don’t overdo adding rich compost and fertiliser before planting, but it does like the soil to remain moist in summer. It also needs a position out of full, strong direct sunlight, preferring light shade, although it can also grow well in quite gloomy positions.
    Also, much can depend on the type of planting material you’ve use. If you buy dormant, pre-packed roots, they may have dried out so much that they will always struggle to grow. It is far better to buy potted plants – and buy and plant them in spring when they’re already in leaf.

  • Question What is the kindest way to get rid of moles without killing them? I have tried to thump the ground, which has not been very successful. I have also tried pouring water down the hole, but they are a persistent lot. Answer

    Trapping is the only really reliable method to get rid of moles – but you must do it correctly. Handle the trap with gloves (the moles mustn’t get a whiff of human scent) and don’t put the trap in the molehill. Instead, find the run between two molehills by testing with a metal pole or similar and put the trap there, covering it over to make sure that no light whatsoever will get into the run. You can buy humane traps that trap, but won’t kill them.
    Some people put mothballs or similar strongly scented materials into the run, or use one of the battery-operated scarers – or even a child’s windmill – moles hate vibrations.
    Another option is to try and flood the run with water – you need to do more than just pour water down the run – or you could find out if you have a local “mole man”, who might be able to help.
    I know people that swear by using human male (female won’t work) urine poured into the run – and numerous people have told me it works. Again it’s the smell that deters them.

  • Question My begonias are suffering with powdery mildew disease. What is the best way to treat it? Answer

    Powdery mildews are usually worse on plants that are under stress – particularly if allowed to dry out at the roots. Make sure you keep the soil/compost they are growing in moist to help prevent this.
    As powdery mildew spores need a layer of moisture on the leaves to germinate, you should always try to water the soil/compost, but keep the leaves dry. I know, not always possible! Also, make sure you feed with high potash feeds; these will help toughen up the growth, whereas high nitrogen ones produce soft/susceptible growth.
    You can spray the plants with a systemic fungicide, such as FungusClear Ultra or Bayer Garden Fungus Fighter. Just be aware that fungicides always work better as a protectant than a cure, so are best applied early to protect the growth from attack.

  • Question I have two hydrangeas growing in pots. When I purchased them the flower colour was blue. Now, they’ve turned pink. What can I do to restore and maintain the original colour? Answer

    Hydrangea flower colour is dependent on the pH (acidity/alkalinity) of the soil/compost they are growing in. They are blue in acidic conditions and pink in alkaline ones. If you planted them in ordinary compost, rather than ericaceous compost, this will have started their change to pink.
    You can buy a hydrangea bluing powder (such as Vitax Hydrangea Colourant), which is based on aluminium sulphate, from garden centres. Or you can try and acidify the compost with sulphur chips. But if you have hard/alkaline tap water that you use to water them, they will always struggle to revert back to blue and, as a result, they take on a horrid pink/blue piebald colour. In this case, it’s often best to just enjoy them being pink!

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