Horticultural

How to care for African violets

Here's the first of a series of posts about my favourite houseplants: a sorely neglected subject that I am hoping to write more about in the coming months.

Number one: the African violet
The plant pictured here is my all-time favourite African violet: I love the colour combination and the candy-stripe look.

African violets, or Saintpaulias as they are properly known, are easy plants to grow, making them extremely popular plants - you can buy them just about everywhere, from garden centres to petrol stations.

Unfortunately, they also have a reputation as being hard to grow, and I frequently wince when I see tortured-looking clumps of miserable looking Saintpaulias on a windowsill in someone's house. Follow these few top tips - either with a newly bought plant or to rescue a poorly specimen - and you should find your violet will flower almost all year round.

Tip 1: watering
The most common mistake with this plant is overwatering. Remember, its leaves are fleshy and hairy, meaning it is adapted to dry conditions that it finds in its native homelands in East Africa. Only water the plant when the soil is bone dry, and it won't harm if you even wait until the leaves start wilting: cut back even further on watering during the winter months to encourage the plant to rest. The second key point is that the leaves hate being splashed with water, so add water from below and allow the plant to suck up what it needs - but don't let the pot stand in water. Books also counsel against using really cold water, so I usually pour on the remains of a long-abandoned bedside water glass that's reached room temperature.

Top 2: suckers
People often end up with unsightly humps of non-flowering Saintpaulias because they allow baby plants that grow from the base to grow unchecked. Given time these will compete for space with the adult plant and result in an unattractive clump. Instead, check regularly for baby plants by gently lifting up the leaves: if you see any, cut them away with a penknife, taking care not to damage the stem of the adult plant. If you are careful and they come away, you can try potting them up and propagating them as a new plant. If that sounds like too much work, just add the excess leaves to your composter. Remove damaged outer leaves: if this leaves you with a "stalky" plant, you should repot it, covering the stem with soil to the point where the first leaves spring.

Tip 3: sunlight
They light bright light but not direct sunlight - a west- or east-facing windowsill is ideal. It will survive but not thrive in deep shade. They will tolerate most domestic conditions temperature-wise, but if you like the central heating at full blast, they'll probably benefit from being sat on a dish filled with moist gravel to increase humidity levels.

Tip 4: dusty leaves
If your plant's leaves become dusty, or infested with whitefly or aphids, it's easiest to remove the problem with an old makeup brush, dragged in the direction that the leaf's hairs go.

There's more info from African violet experts here, or add your own tips below ...

The latest addition

I was given this for my birthday: my first ever orchid. Gorgeous, isn't it? I've always loved the blooms of these exotic plants, but never dared to own one. But this, a Phalaenopsis, is one of the orchids that is relatively easy to grow in one's own home. Lots of people buy these, and they flower and then die back, never to blook again. The challenge will getting it to flower again.

I thought I was doing everything right: not too warm, good humidity, water about once a week; except now I read some further instructions on its care I realise that I shouldn't have used water from the water softener on it. I hope it'll survive one dose, and have now vowed to give it only the finest rainwater.

Anyway, the orchid has given me something beautiful to look at over the last few days, from my sick sofa. I think it could be another week or so before I am back to full strength: I am concentrating on getting well so I can: a) finish the book, and b) get down the allotment.

And while I welcome this new plant, I am steeling myself to say goodbye to the Croton that got scorched by steam from the kettle and is now looking very sad. I always find it hard to consign a plant  to the compost heap that's brought colour to my kitchen. On the other hand, I've already bought another croton to replace it, and there's nothing worse than the sight of a sad specimen that's past its best. Given how cheap houseplants are and how many I have, I really shouldn't be so reluctant to encourage a bit of stock rotation.

(Almost) total recall

I guess I was an unusual child.

I spent a lot of time reading books about houseplants, and memorising their Latin names. Strangely, I have never forgotten those tongue twisting titles and I'm prone to blurting them out at embarrassing moments: when someone shows me a new plant they've bought I'll say "oh, that's a lovely Dracaena marginata triclour!" It can be rather disconcerting, I know, but it does serve a purpose.

When Lynda Penlington emailed me a picture of a houseplant she wanted me to identify, I couldn't quite place it. Then, a few minutes later while doing something else entirely, I suddenly exclaimed "Pteris certica!"

I was very nearly right, although after consulting my houseplant bible, DG Hessayon's The Gold Plated Houseplant Expert, I think it's actually the closely related Pteris ensiformia victoriae. They're both ferns: indeed Hessayon desrcribe's Lynda's variety as "the prettiest of all the table ferns".

The ferns are a huge family of houseplants but they all need roughly the same care: a humid environment, moist soil and indirect light (but not shade). The Pteris types are among the easiest to grow, which is why they are so popular as plants.

Post-Christmas houseplant advice

Jackie Harmer has emailed me this photo of a succulent arrangement she's been given and has asked for some advice on how to look after it.

The first thing to do in this instance is to identify the plants, as different plants need different care. After scrutinising it rather carefully I think the green plant in the front right is a jade plant, or Crassula argentea: the pinky-purple ground-hugging rosette in the foreground is some kind of Echeveria, and the tall thin plant with variegated leaves in the centre could be a small variety of small-leaved peperomia. The one I am least sure about is the green plant with red-tinged leaf edges at the back left of the jar - a kalanchoe possibly? Although it would probably be flowering were that the case. Anyone got any clearer identification on that one?

More importantly than pinning down the identity of each individual plant, we can say that they all fall roughly into the family of succulent plants: those with fleshy leaves or stems that can store water. The good news here is that they are the tough guys of the houseplant world, able to put up with a lot of neglect and mismanagement without keeling over in the way a lot of more delicate plants would.

It's more than a little unfortunate that these succulents have been sold in a jar, albeit a semi-open one, because the one things succulents love is fresh air. Jars are useful environments for houseplants that originate in subtropical of tropical climes, as they provide the extra humidity our centrally heated houses often lack. The other problem is there won't be anywhere for excess water to drain away, which is something else the plants inside won't like. (I could go on and on about how inappropriate plants are sold in supermarkets but that's for another post, I suspect).

The jat shouldn't be too much of a problem for the first year or so, but the jade plant in particular will very quickly outgrow the confines of the glass and conditions will become very squashed. For the moment however, as it's winter, there's actually very little you need to do with this arrangement aside from enjoying looking at it: water very sparingly (once every month is fine) and make sure the plants are on a bright windowsill in a cool room.

Once winter's over, the arrangement should be treated as an ordinary houseplant: water whenever the compost (I hope there is some compost under the stones!) is dry and place on a south-facing windowsill if you can. Most people deny cacti and succulents water because they think they like desert conditions, and while they are adapted to survive dryness, they are much happier when watered regularly. Given the lack of drainage in the jar, little and often is best: lift up the jar regularly to check water isn't pooling at the bottom. If you can, place the jar outside on very warm summer days to get some air circulation, but keep it out of the direct sunlight or the leaves may scorch.

When the plants inside begin to look weak or straggly, or they outgrow the jar and start poking out of the hole, unless you are particularly attached to the jar, I'd (carefully) break it and repot the constituent plants in sandy houseplant compost topped with gravel in a shallow terracotta dish, where they'll be much happier. If you want to keep the jar you'll have to struggle to get the plants out of the hole. Then I'd replant it with a small specimen of something like the pretty foliage plant Fittonia argyroneura.

How to care for your Christmas tree

So it's nearly Christmas eve, and you may have had your Christmas tree for over a week now. If it's a plastic one, you're laughing: but if it's a real, living tree, there's the worry that you're going to trip down the stairs on Christmas morning and find Santa has brought you a floor full of pine needles.

Here are a few tips for keeping your tree in tiptop condition this festive season:

• When you buy a tree, choose one with stiff, hard needles that show no sign of dropping when you brush past it or shake it. If it comes with its roots or trunk in damp sand or soil, all the better. (If you're like me and allergic to pine needles, wear thick gloves whenever you touch the tree).
• When you get the tree home, stand it outside and wash the branches off with a hose to dislodge soil and insects. When you're ready to decorate it, saw a fresh base to the trunk, cutting diagonally to maximise the surface area of wood available to take up water.
• If you can, place your tree in a specially-designed stand that can be filled with water: check the water level every day and make sure it's topped up to at least an inch above the base of the trunk. If the tree is planted in soil or sand, keep it moist but not wet.
• Friends of mine would add always add half an aspirin or a spoonful of sugar every so often to help keep the tree fresh, or add cheap lemonade to the water, as you would do with flowers. I've tried this too and it seems to prevent needle drop.
• Remember: this is a tree! It's used to being outside. Try to stand it well away from radiators or air ducts and keep the heating as low as you can comfortably go, especially at night.
• Accept that some needles will fall, whatever you do. Keep a Dust Buster or old-fashioned dustpan and brush on hand to keep them tidied away.
• Always turn Christmas tree lights off at night and when you go out to prevent a fire risk.
• Once the festive season's over, make sure you recycle your tree: many local authorities will take yours away for you and turn it into compost or mulch. Or simply chop it up yourself and make a hibernation spot for hedgehogs under a fence or hedgerow in your garden by placing the branches in a bundle to slowly break down of their own accord. The hedgehogs will like it if you add a few leaves, too.

Well, that's it from Horticultural now until after Christmas. I do hope you all have a wonderful festive season and are looking forward to a happy and healthy 2006.

It's hot, damn hot

It only takes a single weekend of moderately warm weather to bring many people out in a rash of moaning that it's  "too bloody hot".

Having lived in Baton Rouge, Louisiana for two years a while back I take a different attitude, revelling in stories of 100% humidity, 33C August days in the deep south in a car without air conditioning (I was a poor masters student at the time) in the manner of the Monty Python four yorkshiremen sketch.

But hot weather does mean you have to take extra care of your houseplants and outdoor plants, particularly those that don't hail from warm parts of the world. Here are a few tips on what to do in hot weather:

• Don't water plants in the heat of the midday sun: early morning or late evening is best. But if it's a choice between watering at lunchtime or not watering at all, throw that rule out the window
• If you have houseplants that like cooler conditions, spray them with water, move them away from bright light and water regularly
• If you have cacti or succulents, put them outside in the sunlight and give them a good dousing: they'll love the fresh air and sunshine. But make sure you move them back before it gets chilly.
• Mulch is key to helping your soil retain water. Add whatever you can - newspaper, grass cuttings, black plastic - to the surface of the soil and you'll find your plants will be far happier
• Water your outdoor container plants and hanging baskets twice as often as you think they need it
• Sink plastic bottles next to thirsty plants such as squash and tomatoes - pour the water into the bottles and it should get straight to the plants' roots rather than draining away. Otherwise scrape out a little indented circle around each plant so that the water pools around the plant
• Save water by using "grey" water from your washing up and bathing - once it's cooled down, naturally. Provided you don't use this water on the same spot every day, it shouldn't have any impact on your plants, especially not if you use "eco" washing up liquid

And finally, don't forget your own welfare: while gardening in the heat, take lots of breaks, drink as much water as you can and put off the more strenuous tasks until later in the evening when things have cooled down. And remember to put suntan lotion on the places that can be exposed when you're bending down to tend to your plants. The lower back - often exposed as you squat down and your T-shirt rides up - is at particular risk from the lobster look if you don't.

Potting on

When it comes to time off from work, if I am not away on holiday, there's nothing more satisfying than a bit of houseplant maintenance/allotment work/gardening to keep me out of trouble.

Today the weather can only be described as "filthy", so allotmenteering/gardening is out: instead I decided to repot a 3ft tall Dracaena marginata that had become seriously pot bound. I forgot to mention this problem in my houseplant care notes below, but if a houseplant of yours is looking really sad (wilting or yellowing leaves, not growing at all, looking dull or lifeless) and you've tried everything else, it could be that it's potbound. Of course, there are plants that actually like being potbound: just check your houseplant book to see if this is the case for the plant you're dealing with. If it is, you probably shouldn't repot it.

Potbound means exactly what you might think. The plant's roots - which naturally want to spread out in search of water and nutrients - will eventually become crammed into the confines of the pot, and the plant will start to suffer.

The picture to the right is the dracaena's roots prior to repotting - it was seriously potbound but it was such a tough cookie that it was only just starting to show the signs. The answer is to repot into a container about 5-10% bigger than the current pot, adding new compost (I recommend  peat-free houseplant compost).

Make sure you tease out some of the compacted roots so they can spread into the new compost, and water well straight after planting. I'd also recommend covering the surface of the compost will small pebbles or gravel - not only does it look attractive, but it also reduces the risk of mould growing on the soil, which can be an irritant to asthmatics.

Why your houseplants die ... and mine don't

As someone with a reputation for knowing a bit about plants, the most common question I get asked is "why do my houseplants always die?" - a query often accompanied by a finger's jabbing motion towards a sickly spider plant, shrivelled cactus or other torture victim.

Below is a "potted" summary of the advice I usually give people. Of course, every houseplant variety is different, and generalisations are exactly that - general rules to which there will always be exceptions. But try to get these bits right, and with any luck your plants will thrive. Or at least they might die a bit slower.

1. Is it a pot plant or a houseplant?

Important distinction, this. Plants grown in houses fall into main groups: pot plants, which are grown to be bought, placed in your house and enjoyed until they die a few weeks or months later (often when they finish flowering), and houseplants, which should live for several years, with care and attention. (Think annuals and perennials in the garden, or, if you're British, Eldorado and EastEnders.) In other words, if you are complaining because the potted chrysanthemum or poinsettia you bought three months ago is dead, stop beating yourself up about it: it was MEANT to die.

2. Where the hell are you?

Remember that, climate-wise, your houseplants are fishes out of water. Most plants we try to keep in the warm, bone-dry air of our luxury pads come from humid subtropical or tropical parts of the world.

That's not to say you need to water them every day in a rainforest-style deluge. In fact, the most common reason plants suddenly collapse is too much water: an underwatered plant will die too, but much more slowly. As a very general rule, plants need watering in the summer when the soil about one centimetre below the surface feels only very slightly damp, preferably before they dry out completely. In the winter, cut the watering back to about a third of the frequency of the summer (although this may not be the case if you keep you heating on high throughout the winter).

The other way you can mimic houseplants' natural environment is by upping the humidity. There are various ways of going about this: either by grouping the plants together to create a microclimate, or by introducing a source of humidity by spraying the leaves with water or placing pots on a gravel tray.

3. It's dark in here ...

This may sound dead obvious, but your plants need light - natural light. Most light bulbs don't give plants the right kind of light for them to use in photosynthesis, so a plant in a room with no daylight will feel as if they're in complete darkness. Again, it varies from plant to plant, but make sure that your plant has some source of natural light. If you want to know more, read on here.

4. You've been sold a pup ...

Many of the attractive houseplants sold by your local supermarket or garden centre are, to the expert eye, like a frisky racehorse being bought by someone whose equestrian experience is no more extensive than a donkey derby. It doesn't always follow, but many of the most beautiful and unusual houseplants are also extremely exacting about their environment: think J Lo's rider when she is on tour rather than Billy Bragg's.

So if you want to shell out on some new plants that will make your home look good and thrive without an awful lot of care and attention, avoid orchids, carnivorous plants, caladiums, crotons, bromeliads, ferns with delicate leaves, and ivies (often sold by the latin name, Hedera - they're much better suited to conditions outside) and indoor bonsai. I know that sounds like a big list, but there are plants you can grow that are tough and beautiful. As a rule of thumb, it's hard to go wrong with classics like the parlour palm, dracaenas, rubber plants, aspidistra (I've always fancied a variegated one), cacti, succulents and the umbrella plant.

But there's no substitute for spending five minutes with a houseplant book (this is my bible) checking that you're not about to pick something out that's more high maintenance than Liz Hurley. This will also advise you whether it should go in the blazing sunshine of your south-facing windowsill, or in a cool, shady conservatory.

If you have a houseplant query, just drop me an email or leave a comment (a picture really helps) and I'll try to help: and if I can't, I can probably find someone who can.

An altogether classier Jade

I solved my office plant dilemma with the purchase of this little fellow from Ikea: a jade plant or Crassula ovata. If I was into feng shui (which I'm not) I'd also be hoping that this plant would bring me wealth. It has rather lovely fleshy leaves and a constitution that's tougher than Anne Robinson on steroids.

With any luck this member of the succulent family will thrive in the air-conditioned confines of Guardian Unlimited towers: the only major risk is being mistaken for an ashtray by an errant night worker.

Then again, it might shrivel up and die like the last parlour palm I tried to bring into the office. I'll keep you posted.

Oh, and the rather groovy handmade pot? Car boot sale, circa 1999, somewhere in the home counties ...

The Wardian keyring

Thanks to Gizmodo for this post about a new form of keyring (keychain if you're American) that consists of a tiny cactus or succulent inside a miniature plastic globe. The growing medium looks as if it's prevented from shifting about by a plastic disk with a hole for the plant to grow through. Apparently they retail for $10 and can be transplanted into a regular pot when they begin to outgrow the dome.

The idea of growing plants inside a sealed environment isn't a new one.  Gizmodo (perhaps not a regular user of botanic terminology) incorrectly describes the keyring as an arboretum,  but these inventions actually stem from the Wardian case, which was thought up back in the 1830s. Jenny Uglow writes in her excellent book A Little History of British Gardening:

Dr Nathaniel Ward, an amateur naturalist, had noticed that a tiny fern grew perfectly in one of the glass jars he used to pupate caterpillars: it was sealed, and the moisture condensed by day and returned to the plant by night. He developed larger cases to transport plants, providing a sealed environment protected from the salt and winds and extremes of temperature that had ruined so many specimens in the past.

There's a little more on the history of Wardian cases at Terrariums.net. The only problem I can foresee is that, if like most people, your keys spend a lot of time buried in a deep and usually hard-to-locate corner of your bag, or in your pocket, the plants won't thrive.