Q&A - Climbing Plants

Q. Please can you give me some advice on what's wrong and how to improve the health of my two Akebia quinata. I bought them earlier this year and have trained them up a garage wall where they were green and lush. They are well sheltered, although they don't get much sun. I check the soil and water as necessary, adding some tomato liquid feed once every two weeks. The books I've looked in say that Akebias are relatively trouble free but mine now appear very spotted and yellow.

A. The most likely cause is red spider mite, which would explain why the new growth is green and lush in the spring. Whilst a bit unsightly the pest is unlikely to survive the winter in any numbers but if noticed in spring/summer they can be sprayed with an appropriate pesticide if necessary.

Q. I have a clematis that is growing in a large tub that also has a broom growing in it ( the clematis, is climbing up through the broom). The clematis has developed brown blotches on its leaves and has not flowered. Why do you think this is?

A. The leaf blotches and non-flowering are unlikely to be related. The fact that flowers have not formed is most probably down to your pruning. As a general rule early flowering varieties produce flowers on old wood and should therefore be pruned immediately after flowering whilst later flowering types flower on new growth and should be pruned in early spring before or as soon as new growth starts. The leaf blotches are most probably caused by a fungus, which is quite common especially in wet seasons as this spring was. You can spray with a systemic fungicide such as NimrodT but it is preferable to remove the leaves and burn them, as new ones will grow. You should also feed your plants with a general fertiliser.

Q. On the south facing wall of our house there is a climbing hydrangea, it was at about 5' tall when we moved in, in late 1999. So far is has grown a little in height, and looks very healthy with lots of good strong leaves, but has not flowered yet. It is in a huge pot, could that be something to do with it, or is there something else I need to do to get some flowers next year?

A. Climbing hydrangeas (Hydrangea petiolaris)can take quite a few years to establish before they flower but as you have it in a pot it may not be getting the right balance of food. Try watering with a high potash liquid feed from September (Tomato food is ideal) and then remove the top 10cm or so of compost. Replace this with a mixture of fresh compost containing loam (soil) and bonemeal fertiliser and keep well watered throughout the year. Repeat this process annually.

Q. Could you tell me about Dutchman's Pipe Vine? On my families original homestead there is a vine. But no one has ever been able to get it to grow elsewhere. The flowers look like a Tobacco Pipe just like the Dutchman's. Have you ever heard of this vine?

A. The correct name for Dutchman's Pipe is Aristolochia macrophylla. It likes most soils that are not too heavy and needs them to be well-drained but moisture retentive. This can be achieved by adding plenty of organic matter such as well-rotted manure or compost which they thrive on. A sheltered spot in light shade is preferred and a minimum winter temperature of 15 degrees Celsius (59 F) can only be tolerated. It can take 2 years to establish the plant before really strong growth is produced.

Q. We are looking for a hardy climber for a north facing wall to be grown in a pot. The area is not large so we do need a very vigorous plant. We already have jasmine and honeysuckle and ceanothus. Any further suggestions?

A. There are a number of Clematis Hybrids that are particularly suitable, Nelly Moser is very reliable but you could also try Carnaby, Dr Rupel, Elsa Spath, Fireworks, Lasurstern, Lord Neville, Miss Bateman, Niobe, Snow Queen. Also small leaved ivy such as Green Ripple or you could try wall shrubs like Chaenomeles, Euonymus Silver Queen or Pyracantha.

Q. Can you please tell me why my honeysuckle has only produced a few flowers this year? I pruned it hard last autumn and it has produced hundreds of healthy shoots, which are all full of leaves, but no flowers.

A. Plants sometimes don't flower well the year after they have been cut back hard as they are too busy putting on new growth. Try not to give the plant any more feed this year and you should get a mass of flowers next summer. You also might find that the plant flowers later in the summer when the main flush of growth has finished.

Q. Can you give me information on pruning passifloras

A. Your Passifloras should be pruned the same whether they are grown inside or out except that outdoors they may be killed back to ground level in very cold weather. In Feb/Mar thin out overgrown plants by cutting off selected shoots at ground level or back to the main spur. Side shoots should also be trimmed back to about 15cm (6") at the same time.

Q. Can a passionflower be moved, if so how and when can it be done?

A. Yes you can move a Passionflower but you will have to be careful to try and dig up as much of the root as possible with soil still round it. Any time in early autumn or spring would be fine, providing you keep it well watered after planting, although mid spring is often thought the best.

Q. I have a mature passionflower which gave one solitary fruit this year. I
am moving house and would dearly like to bring on a new plant to take with me. What is the best way to ensure germination?

A. Passionflowers are not the easiest of plants to grow from seed but you can try sowing seed in pots of seed compost, just covering them with a fine layer of compost. Cover the pot with a plastic bag to keep the moisture in, removing it when the first seedlings appear. Place in a warm place with a temperature of 18-21 degrees Celsius(64-70 F). Prick out the seedlings when they are large enough to handle into 9cm pots and grow on in a frost free but light place.

Q. I would like to grow wisteria and I have heard it can be difficult. Does it need lots of sun or shade and in what form is it the best way to buy. i.e. as a small tree from a centre, as a clipping?

A. Wisteria is not difficult to grow but it is best to buy a plant that has been grafted as it will flower within 2 or 3 years, whereas seedlings can take 7 or more years to flower and you really can't be sure how good the flower colour is. The best position is in sun and a well-drained soil that still holds moisture. This can be achieved by digging plenty of well-rotted manure, compost or similar organic matter in to the soil. You will need to provide wire supports against which to train the plant and it will need pruning each autumn and February to flower reliably. You should cut all side growths back by two thirds at the end of autumn and then reduce these further to two or three buds in Feb/March each year.

Q. I have managed to get some seeds from my Wisteria to start to grow indoors, but now I am unsure of what should do as they appear to be growing rather quickly.

A. Your Wisteria seedlings should really be resting outside in a cold frame or glasshouse at this time of year. If this is not possible find a cool place for them in the house. Keep them just moist and then in the spring pot them into a slightly larger pot and leave them outside until they are ready for planting out. Seed raised Wisteria may not necessarily produce flowers of the colour or size of your mother plant and it will be some time before you will know if you have a good plant or not.

Q. Can you please tell me when and how do you prune a young wisteria (2yrs) and when is the best time of the year. It is approx 3ft tall very bushy on top but very little on the bottom which is thinly covered.

A. Wisteria are generally not bushy at the bottom. You should select the strongest stems that you want to make the framework of the plant and train these against wires on your wall or fence. You should cut all side growths back by two thirds at the end of autumn and then reduce these further to two or three buds in Feb/March each year.