Facebook Questions and Answers for the 1st August 2014

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Hello Facebook fans, thanks for your questions this week, here are Carly's replies:

Martine-Tina IH Pell

Hi I have created a hedge using Buxus plants, when we planted them out they were lovely and green now some of them have turned an orangey colour is this normal, we water and feed them but don't know what is causing this, thanks x

Hi Martine-Tina, it sounds like your plants may be experiencing environmental stress and as they are young they will be more susceptible. Orange or bronzed leaves are most often seen when box plants experience very hot and sunny conditions, often combined with dryness at the roots. Conversely this is sometimes seen when the plants are waterlogged too, although this most often occurs after a wet winter. Box actually prefers a part shade of fully shaded position and intensely sunlit areas can cause sun scald or discolouration to the leaves. As your box plants are very young, they have small root systems so take care to water them thoroughly in dry weather. You probably don’t need to feed them unless they’re growing in containers, to give them a chance to establish a deep and healthy root system. Make sure the plants aren’t in an exposed, windy part of the garden as this can also cause stress. Your plants should recover in the autumn once the weather cools and the sunlight is less intense. I hope this helps.

Tina Hughes

I have 2 questions if that's ok? I want to get a clematis to cover a fence, which ones don't have to be cut back? Is it possible to save fuchsias and geraniums for next year or do they just die? Thank you.

Hi Tina, group 1 Clematis require little or no pruning; they include most evergreen varieties and those which flower in the winter and spring. You can find out more about group 1 Clematis, including good varieties to grow, in our 'How to grow Clematis' article. With regards to fuchsias and bedding geraniums (Pelargoniums), they are perennial in their native habitats so can be saved for next year. However it does require a bit of effort and space so I often find it better to buy fresh, vigorous new plants each year! To over-winter them, bring them under cover before the first frosts. If they’re planted in the ground you will need to gently dig them up, taking as much of the root ball as you can, and replant them into pots of multipurpose compost. Pot all the plants up individually and cut the stems back to about 10cm (4"). Check the underside of the leaves for pests and treat any infestation as soon as possible, as they will quickly multiply once under cover. Water the plants and place them in a bright, cool (but frost-free) greenhouse or conservatory. A cool windowsill would also be fine.

The secret to over-wintering geraniums and fuchsias is to keep the compost almost dry during winter as they are very susceptible to rotting in cool conditions. Keep an eye out for aphids too. When the weather begins to improve in spring you will start to see small signs of growth and this is your cue to gradually increase watering. You can also give them a general purpose feed in spring to encourage strong growth. You can plant them out again after the risk of frost has passed in May next year. I hope this helps Tina, best of luck.

Susan Macmillan

What do I do with my agapanthus in the winter so that it flowers again next year?

Hi Susan, Agapanthus range from being fully hardy to half-hardy and anything in between! The evergreen varieties tend to be less hardy than the deciduous ones, although both types require a cold period to flower well. Most varieties sold are deciduous but if they are evergreen it should be mentioned on the description. Deciduous agapanthus should happily survive winter in the ground provided you offer them some protection. In autumn or early winter spread a thick layer of dry mulch, such as straw or bark chips, over the agapanthus plants aiming for a layer 15-20cm (6-8") deep. Remove this layer in spring when growth resumes. All agapanthus plants like free-draining soil so if yours is prone to becoming water-logged then it might be best to grow them in pots which can be placed somewhere sheltered for the winter. Evergreen Agapanthus are best brought under cover to a greenhouse or cool conservatory throughout winter. If you’re over-wintering the plants indoors, water sparingly so the compost is just moist. Avoid lifting or dividing plants too often as Agapanthus resent disturbance and this will reduce flowering. With some sunshine, water and fertiliser in the spring and summer months, your Agapanthus should continue to put on a magnificent display every year. I hope this helps Susan, best of luck.

Kath Baker

I have a tall mature north-facing privet hedge which must stay. I had a silvery leaf deadnettle planted in the border by it semi-successfully. Any other suggestions? It gets a little direct sun in summer. The hedge must get most of the nutrients and water!

Hi Kath, you’re probably right in that the privet hedge will have an established and widespread root system. Deadnettles prefer a moist soil so if the plant was struggling this may suggest that the soil is quite dry or compacted. If you haven’t already, it would be a good idea to dig over the border and work in plenty of well-rotted manure, compost or recycled green waste. If possible, try to plant 45cm (18”) away from the base of the hedge to allow for the hedge’s root system. I would choose plants which cope well with full or part shade. We have an excellent list of plants suitable for dry shade in our 'Plants for shade' article. I hope this helps Kath, good luck.

Hayley Smart

Hi, I have a question please. I have 3 well established blueberry bushes that have always been in pots for years. I want to plant them out for next summer so when is the best time to do this (autumn?) I know they like ericaceous soil so shall I buy a bag of that and dig this in when I plant them out? Do I need to prune them harshly? Finally, in the 2nd photo there are these tiny dry little brown oval things all over the stems! What are these? Shall I get rid of them and how? Sorry for the multiple questions but I do love my blueberries! Thanks.

Hi Hayley, autumn is the perfect time to plant out blueberry bushes. You’ll need to make sure your soil is naturally slightly acidic before planting; working in ericaceous compost will only be a short-term solution as it will be broken down in the soil. Try buying a simple soil pH tester kit to confirm the acidity of your soil. If your soil is close to neutral, you can acidify it by using sulphur chips before planting, although they will need re-applying every few years. If your soil is alkaline it will be very difficult to grow ericaceous plants such as blueberries, even with the addition of sulphur, so they would be best grown in pots permanently. To re-pot your plants, you can either pot them up into larger containers or root-prune them in the spring by trimming away one third of the roots and compost and teasing out the remaining roots slightly. Pot the plants up into ericaceous compost and water well. Pruning should be carried out as normal, regardless of what you do – you can find out more about blueberry pruning with our 'How to grow blueberries' article.

With regards to the brown bumps on your blueberry stems, these look like scale insects. They are sap-sucking insects which affect the general health of the plant so are best treated as soon as possible. It’s best to spray the plants with a systemic insecticide at this stage – there are many available. Look for the ingredients thiacloprid or acetamiprid on the container and check they are ok to use on fruit bushes as not all will be suitable. You can also buy winter washes which are applied when the bushes are dormant from late autumn onwards, and will control the over-wintering young nymphs (not the adults unfortunately). Vitax winter wash is an organic product so is well worth using to prevent further scales developing. The scale insect’s shells will remain on the plant, even after death but new growth should hopefully be free of scales. I hope this helps Hayley, best of luck.

Julie Goodwin

I also have a blueberry question. I have two bushes which have produced a fair bit of fruit this year but they have barely any leaves. There are some and the odd new shoot but the stems are pretty bare. They are in terracotta pots in a mix of two thirds ericaceous and one third multi-purpose compost. They've been in the same pots and compost for two years. They just look a bit...bleurgh lol. Any tips?

Hi Julie, it sounds like your blueberry plants may be slightly stressed, despite the good crop. It might be worth tipping the plants out and inspecting the root balls – vine weevil larvae do like blueberry plants and they start to do noticeable damage at this time of year. The larvae are small, white and C-shaped with a light brown head. If you do have vine weevils take care to only use organic treatments as chemical drenches are unsuitable for edible crops. It might be worth inspecting the branches and leaves for any other pests which could be causing problems, such as scale insects. Blueberries also like a consistently moist soil; they naturally grow in damp areas in their native habitat so take care not to let them dry out in hot weather. As with many fruit bushes, blueberries need plenty of nutrients to keep them happy so try applying an ericaceous fertiliser following the manufacturer’s instructions. You may want to think about re-potting the blueberries in the spring as they will be approaching their third year in a pot. The larger the pot the better, although you can re-pot into the same container if you root-prune the bushes. In spring simply trim away one third of the roots and compost and tease out the remaining roots slightly. Pot the plants up into ericaceous compost and water well. I hope this helps give you some ideas Julie and that your plants recover soon!

Hortentsia Vaughan

Hi Carly. I have some lovely begonia baskets grown from your plugs. Last year they formed the tubers and I saved them, but when I went to get them out the garage to chit they had been munched by weevils that must have been in them when they were lifted. Is now the right time to drench the basket compost with weevil killer or should I wait until later in the season? I would like to keep the nicest shades for next year you see. Thanks.

Hi Hortentsia, sorry to hear about the vine weevil attack – they do enjoy begonias tubers and do the most damage between and autumn and spring. If you’re using a chemical drench such as Provado vine weevil killer then now is the perfect time to apply it, as this will kill the young larvae before they’ve had a chance to do much damage. The Provado product gives protection for up to four months so will prevent any more larvae developing through the autumn. You can then apply another drench around April time when the adult weevils start laying their eggs again. With a couple of treatments each year you should have full control over them. If you prefer organic treatments then you can use nematodes which are also watered into the soil. They are best applied in August or September when the soil temperature is reliably warm as they are a living biological control. I hope this helps.