Facebook Questions and Answers for the 25th March 2011

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

Sam Danyluk

hi, i am after some more advise....i have an arch at the end of my decking, that i am putting 2 clematus plants up it for the summer months....but ideally i would like to use something that is evergreen, preferably flowers in the summer but keeps form in the baron winter months...i know its alot to ask but there has to be somethin out there to fit the bill, thanks x

Hi Sam, this sounds like an ideal spot for a honeysuckle. I find honeysuckles are a great choice as they not only grow fast but they also produce deliciously fragrant flowers too. Lonicera japonica 'Halliana' is evergreen so will provide winter interest along with fragrant flowers in the summer. You could also try honeysuckle 'Gold Flame' which is semi-evergreen with orange-yellow flowers. Another fantastic plant for an arch is a climbing rose. There are many semi-evergreen varieties available, a few popular examples being 'Alberic Barbier', 'Felicite Perpetue' and 'New Dawn'.

For something a little less showy you could try Pileostegia viburnoides which is an attractive evergreen climber with heads of small cream flowers in late summer and autumn. An unusual climber is Akebia quinata which has scented purple spring flowers and bright green foliage which is semi-evergreen (although Akebia can be quite vigorous!) You mentioned you already have some summer-flowering clematis growing up your arch. You could always try an evergreen clematis such as Clematis armandii, which is bedecked with fragrant white flowers in early spring. It is however very vigorous, so after a few years you will need to prune it to keep it under control. As Nick mentioned, winter jasmine is a good option for winter/spring flowers although it doesn't naturally twine up its support; it is mainly used as a wall shrub and will need tying in. I hope this has given you some ideas Sam.

Mary O' Donovan

is it ok to sow broad beans outside now or is it better to start them off in pots inside?

Hi Mary, it's perfectly fine to sow broad beans outside now. They are a cool-season crop and prefer low growing temperatures. Sow the seeds about 4cm (1.5 inches) deep and 20cm (8 inches) apart. They are normally sown in double rows with 60cm (2ft) between each set of double rows. Bear in mind that if you have lots of wildlife in your garden you may be giving the local mice a tasty meal. I sow my beans in modules and place them in a cold frame or unheated greenhouse to germinate before planting out. This way I ensure I get the entire crop!

Fiona Kirk

I have a question. Can you grow clematis in plastic pots? I have read some comments that suggest that plastic doesn't insulate well enough for winter time. Thanks. Also can I dig last year's container compost into my shrub beds?

Hi Fiona, for Clematis it would be better to use a terracotta or similar type of pot. Containers should be about 45cm (18 inches) deep and wide for the best growth. Clematis prefer their roots to be cool and in sunny weather plastic will cause the soil to heat up more than a sturdier terracotta pot would. You could use plastic if the pot was hidden amongst a group of other pots, which would afford it some protection from the sun. Unfortunately all containers are at the mercy of the elements in winter and should be protected regardless of the material they are made from. Good drainage is also essential! Place some pieces of broken clay pot or gravel in the base of your container before adding the soil, and raise the container on to bricks or pot feet if possible.

With regards to your spent container compost - this is an ideal mulch and soil improver for beds and borders. I have used it at home with great results. I hope this helps Fiona.

Claire Aldrich

I have a pot of bluebell bulbs that dont seem to flower anymore but just produce lots of leaves instead and i dont know why? what should i do?

Hi Claire, there may be a few reasons why your bluebells have stopped flowering. If they are in a container it may be a lack of nutrients or overcrowding that is causing the problem. It could also be the depth at which the bulbs are planted – shallow planting can cause bulbs to divide and they are then too small to flower. The best course of action is to remove the bluebells from their pot in June or July when the leaves start to turn yellow. Separate out the bulbs, shaking off any lumps of soil, but don't remove the leaves. You may wish to select just the largest, healthiest bulbs to re-plant as these are most likely to flower. Put fresh compost into your container and plant the bulbs at 3 times their own depth.

For long-term displays its best to use loam based compost such as John Innes to fill your container. Make sure you water your container well during hot weather – don't allow the soil to dry out. Next year, try feeding your bluebells between March and June with a high potassium fertiliser such as tomato food to promote flowering. Hopefully you should have plenty of bluebells for years to come! Good luck Claire.

Karl Hyde

Hi. one of my camelias is looking a bit poorly. It is flowering but not particularlly well and it looks a bit yellow in the leaves. It is about 10 years old. I have tried various feeds and suplements but nothing helps. Any Ideas?

Hi Karl, there are several reasons why your Camellia could be poorly. When you mention yellowing of the leaves this sounds like a nitrogen or manganese/iron defiency. A nitrogen defiency causes the plant to have pale leaves and stunted growth and often occurs in light sandy soils or with plants grown in containers. An iron or manganese deficiency causes leaves to turn yellow with the leaf veins remaining green. This occurs due to the pH of the soil being too alkaline. Camellias are acid-loving plants and over time, through watering the soil or compost with tap water, the soil pH can become slightly alkaline. Builder's rubble and water run-off from mortar in the walls can also cause soil to become alkaline.

If you haven't already, try feeding your Camellia with a special feed for ericaceous plants. You could also try using sequestered iron to remedy the yellowing leaves. Both these types of feed should be available at good garden centres. For a long-term solution it is good idea to mulch your Camellia each spring with well rotted organic matter such as leaf mould, or garden compost to improve both the soil fertility and structure in general.

With regards to the poor flowers this could be due to the lack of nutrients but could also be caused by lack of water. Water shortages during bud initiation (in summer the previous year) cause buds to fail to develop properly or to become small and sparse. Make sure the soil is kept moist during hot spells. Digging in organic matter and mulching each year will improve the soil structure and help the soil retain moisture during hot weather. I hope this helps Karl, let us know how you get on.