GROWING HOSTAS

Planting Hostas

Planting in Containers

Hostas and Water

Dividing Hostas

Feeding Miniatures

Slug and Snail Control

Sue proctor hostas header

GROWING HOSTAS

Hostas are shade-tolerant perennial plants which die down in the Autumn and come back each year in Spring. They are fully hardy, originating in China and Korea where winters can be severe.

Hostas are grown mainly for their foliage which comes in a spectacular range of colours and variegations, from blue through a range of greens to yellow and white.

Although usually grown as foliage plants, hostas flower, colours ranging from purple, through shades of lavender to white. Some flowers are fragrant. Hostas come in a huge range of sizes from miniatures only 4” high to giants up to 4’ high with leaves over 18” long. Leaf shapes also vary from thin strap-like leaves to almost circular.

Hostas look good almost anywhere, from beds and borders to gravel gardens and rockeries. They also make marvellous container plants. Miniature hostas look wonderful in troughs, bowls and raised beds.

Hostas are trouble-free except for the eternal task of keeping slugs and snails away. (See below). They enjoy a neutral to acid soil.

Planting Hostas

Hostas, like most perennial plants, enjoy a rich well drained soil. To give them the best start plant in multi-purpose compost. Unless listed as ‘sun-tolerant’ they should be planted where they are likely to be in shade during the hottest part of the day. Morning sun is beneficial to most hostas, especially those with a lot of white in their leaves. Sun won’t kill a Hosta but the thin-leaved varieties may burn in really hot sun. Bright sun will also lighten the colours of some hostas (e.g. turning blue to green-blue and cream to white.)

Planting in Containers

To deter slugs and snails try placing fine mesh over the drainage holes in the bottom of the pot before filling. We find a piece of fine windbreak/shade netting works well. Put crocks, small stones or pea gravel in the bottom of the pot to improve drainage. After your hosta has been in its container a year or so, check the roots. If it is pot-bound, then you can re-pot into a larger container. If you need to keep it in its existing container, a root prune will reinvigorate it. Take off an inch or two of root with scissors or snips and fill the space at the bottom of the pot with new compost, adding a granular slow release fertiliser.

Hostas and Water

Hostas are well-known as moisture loving plants and it’s probably true to say that if you want your hostas to grow quickly and to their maximum size, and to look good all season, then they can take as much water as you can give them. The good news is, though, that hosta roots store water and when we are away at Shows, most of the 150+ hostas in our garden seem to manage very well without extra watering, even during hot spells.

Sometimes though, you may find that a hosta ‘sticks’ after three years or so, and refuses to grow any larger. Unless it’s a variety renowned for this (e.g. H. ‘Great Expectations’, H. ‘Fire and Ice’), then the problem is probably insufficient water. The leaves of large hostas may stop rainfall from getting to their roots. Hostas in pots that have become root-bound or have been allowed to dry out may still have dry roots, even after a heavy watering. Keeping pots in a saucer that is constantly topped up helps here.

Dividing Hostas

Hostas take between 4-7 years to grow into a mature plant, depending on the variety. Some varieties need dividing regularly to preserve their variegation – your specialist hosta retailer will be able to tell you if this is the case. Hostas can be divided as soon as there are multiple ‘eyes’ (little buds) around the crown of the plant. These can often be felt just under the surface of the soil, but be careful not to break them off with a searching finger!. Some slow-growing varieties may take three years or more to reach this stage. Others may be dividable in no more than a year.

To divide a large mature hosta it’s best to wait until spring when you are not battling with too much foliage. Loosen it from the soil as much as you can and then cut partly through the crown with an old saw rather than trying to cut or chop it with a spade. Then tease the parts of the plant apart with two garden forks. This minimises root damage. A very old hosta can be cut into several new plants but discard the thickest, woodiest part of the crown – take the new plants from around the crown.

Smaller or younger plants can be dug up or removed from their container, hosed around the crown to reveal the eyes and then divided with a bread knife. Eyes may not grow evenly around the plant and washing the crown means you can make sure your divisions are of equal size (similar number of eyes on each division). Again cut through the crown and tease the roots apart.

The best time to divide is in spring and early to mid-summer when growth is at its fastest. This gives the divisions time to fully recover the same season.

Feeding Hostas

Hostas will benefit from some help at the beginning of the season, particularly those in pots. The new season’s roots don’t begin to grow until the first leaves have been fully open for about three weeks, so feeding with a root stimulant such as Seaweed Feed is really beneficial between February and May. Hostas are not voracious feeders but some slow growers and those with a lot of white in the leaves, e,g, H. ‘Fire and Ice’ will appreciate a high nitrogen feed (15-20%) such as Phostrogen from time to time.

SLUG AND SNAIL CONTROL

Sometimes it seems there are as many remedies to the slug and snail problem as there are hostas! Here are some for you to try.

Find the culprits!

We go round in the evening just after dark with a torch and pick them off the paths and plants. This is especially effective after rain. Our record is over 390 on a mild November evening! What you do with them then depends on how squeamish you are. If you release them somewhere else make sure it’s over 30 metres (100ft.) away from your garden. Experiments show snails have a homing instinct! If you can’t bear treading on them, (putting them in a plastic bag first saves mess), bag them up and throw them in the bin. If you collect them in a bucket with salty water in the bottom, the deed is done for you. Don’t pour the water on your garden though. 

Get to know where slugs and snails like to hide – anything plastic such as plant pots or sacks in a relatively undisturbed and cool place will soon become a mollusc hotel. We found dozens over-wintering under the rim of a fibreglass waterfall. They also enjoy hiding in the heart of spiky plants such as phormiums, astelia, grasses and kniphofia (red hot pokers). Or of course, at the very base of hosta stems themselves. These can be winkled out with a knitting needle or similar.

When buying a new Hosta, be vigilant. Check it regularly and at the first sign of a leaf being eaten, search around until you find the slug or snail responsible. Quite often it will only be one. If you can’t find it (it may take checks over several days), then use one or more of the remedies below.

Garlic Wash

Spraying plants with a garlic wash is one of the most effective ways of deterring slugs and snails. It’s also a root stimulant and protects against aphids.

Crush two large garlic bulbs in a plastic bag to save mess. Add to two pints of water and boil for 3-4 minutes. Leave to cool outside to avoid a lingering garlic smell in your kitchen. Add two tablespoonsful to 7 litres of water in a watering can. Either drench using a rose or pour into a garden sprayer. Use every one or two weeks on a dry afternoon so that the garlic solution can be more easily absorbed. You should see a difference after 4 weeks.

Pellets

Many people, (perhaps most) dislike using the usual blue metaldehyde slug pellets because of their effect on wildlife. If you do use them, they can be very effective early in the year (mid-February) before wildlife is up and about or during any winter mild spell. As a last resort, apply pellets very sparingly and not right next to your hostas (they are an attractant!) Putting them inside a jam jar on its side helps to keep them away from pets and wildlife.

Use a less-poisonous pellet – there’s one based on ferric (iron) phosphate which simply makes the slugs and snails unable to eat. You should be able to find it in a local garden centre. The one we’ve bought says on the tub: - ‘Growing Success Advanced Slug Killer Pellets – certified for organic use’. Another less toxic pellet is based on aluminium sulphate but don’t scatter it on paths. We’ve found it leaves an unsightly crystal deposit after rain.

Some people have told us that porridge oats have the same effect as ferric phosphate pellets – they swell up inside the slug/snail and they can’t eat. Only useful if you don’t have wildlife or pets that may polish them off first.

Barriers:

Barriers work best when applied early in the season before the first leaves are fully out. Then you can be sure you are keeping molluscs away rather than trapping them inside the barrier.

Copper tape. You can buy this at garden centres although it’s quite expensive. Put it round the base of pots (it’s best when in contact with the ground) or for plants in the garden cut the rim off a large plastic pot, place around the plant and stick the tape to that. Customers have told us that a few twists of copper wire works just as well.

Vaseline or WD 40 smeared or sprayed on pots is also reputed to work.

Something gritty around the plants. Most types of gravel or grit are too coarse to work well. The finer the grit the better, Try cactus grit or poultry grit. We’ve had some success with used coffee grounds (coffee shops may give them to you). They work well until rain turns them into a sludge.

Sheep’s Wool. We find this successful. You can buy wool pellets from most garden centres. Website is www.sluggone.com, Email: sales@growaid.co.uk. This company has recently been taken over by ‘Vitax’.

Pine needles or holly leaves can help.

Traps

You can use upturned plastic pots or empty plastic sacks weighed down at the corners as traps. Beer traps work. Pour beer (or a mixture of honey and yeast) into a container with its rim at ground level. Make sure the container is deep enough to stop the slugs and snails from crawling out.

Biological Control

A microscopic nematode or eelworm can be watered onto the soil. It is effective against soil living slugs but not against snails. Available from some large garden centres or on the Web: www.nemaslug-slug-killer.co.uk