Shade tolerant hostas require a gardeners very close eye

The annual attack of slugs has begun in many gardens.

Slugs and snails are a common name for members of the molluscan class (Gastropoda). They are generally known to have a coiled shell in the adult stage.

Hostas seem to be a first choice of slugs. Tell-tale holes in the leaves mean that gardeners must deal with the invaders promptly.

As a general observation, slugs always seemed to be found in moist, acidic soil. Adjusting the soil pH (level of alkalinity) to at least 7.0 (neutral) or slightly higher, will deter them. Their slimy bodies prefer alkaline conditions.

Slugs avoid gardens where the soil is treated with lime or wood ash. Similar to earthworms, slugs are covered in mucus that allows them to easily glide over the surface of the soil.

The mucus will collect and hold particles of salt, sand or other sharp granules which will lead to their demise.

A well rotted mulch will also help to deter slugs as the pH of compost is near-neutral.

An ammonia spray is also effective to kill them. Add one part of household ammonia to 10 parts of water to make a spray or a drench in a watering can. The ammonia adds nitrogen to the soil. Table salt sprinkled directly on the slugs will dehydrate them.

Always remove old leaves and decaying matter. When hostas are concerned, gardeners must clean out the garden bed on a regular basis.  Keep the matter in a compost area, which is far away from the garden.

Use only commercial slug pellets in extreme infestations. The bait resembles dog kibble so great care must be taken. The chemical composition is very poisonous so it will kill unsuspecting animals.

Snails and slugs thrive in wet shady soil. Inspect those areas frequently and hand remove and destroy all visible snails by stepping on them or sprinkling salt on the slugs. Keeping the bed well weeded will also remove potential homes. Never leave pulled weeds on the ground.

If evidence of snails or slugs is on the plants, tilling the soil around the affected area will expose their homes. Most slugs and snails will burrow just underneath the soil.  

Remove all garden decoration (rocks, logs or statues). Slugs and snails will create homes under any of those.

Many gardeners choose hostas for their attractive foliage, extensive leaf variations, texture and colour (green, blue-green, golden yellow, white or blue). Some varieties have highly fragrant blooms.

Hostas can be chosen as groundcovers, eye-catching borders or as an accent in any garden bed.

Most varieties prefer partial shade while others can handle filtered sun. A few varieties can handle full sun without having a stressed, sunburned appearance. Gardeners need to consult plant catalogues or closely read plant tags to locate those specific varieties.

The foliage on average, will grow to 25 to 40cm tall (10 to 14 inches). Miniatures rarely grow more than 8 to 10cm (3 or 4 inches). Large leaf plants grow to a height of nearly 90cm (3 inches).

Hostas can be started from seed but a more effective method of propagating is dividing the crowns. Early in the spring, dig up the entire clump and pry or cut the crown into 2- or 3- inch eye divisions. Use a sharp knife.

While dividing and replanting, never allow roots to dry out or sit in the sun. Be sure to spread out the roots. Water thoroughly, protect from direct sun and keep moist for the rest of the season.

Either pot up or replant the divisions. Add sand and lots of compost or other suitable humus. Hostas prefer deep, rich, moist soil.

To prevent slugs adjust soil pH using lime or wood ashes. Just before replanting, add organic compost and bone meal.

Once established, hosta can remain in its location for several years. Consider yearly division and soil rebuilding when crowding occurs, plant has slowed its annual growth rate or when foliage shows signs of stress or malnutrition.

After dividing, you may end up with more plants than you have space. Consider sharing that bounty with a friend, neighbour or donate them to a plant sale.

Ron Stevenson is a member of the Fergus Horticultural Society

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