Growing hostas, and protecting hostas from slugs and snails
By Andy McIndoe •
The great Sussex gardener William Robinson said of members of the lily family (with common names including Giboshi, Plantain Lily and Funkia): “Admirable plants for picturesque groups, very hardy, easy of increase by division, thriving in any soil, but the foliage effect is finer on deep rich soil”.
All positive stuff, what he failed to mention was the potential for frost damage on emerging shoots, the irresistible attraction to slugs and snails and the fact that they disappear below ground in the winter. Those of us who have struggled with these popular garden plants for years cannot help but be a little bitter and twisted!
Despite any problems with their cultivation as fashions change in the garden and plants shimmer in and out of popularity hostas endure.
Like ferns and ivies many varieties are not the most striking plants but are excellent in contributing that structured lower layer below eye level. Their leaves are graceful of form, definite and architectural in quality.
Hostas suggest shade but most varieties will succeed in full sun. As a rule leaves are larger and lusher in shade and fewer flowers are produced.
In sun the foliage is smaller and more compact and plans are freer flowering. Ideally the ground should be kept moister on sunnier sites. Hostas like a soil that is rich in organic matter so on shallow soils and sand be sure to add plenty of compost or well rotted manure.
Growing Hostas in pots is a potential solution to the devastation of slug and snail damage. Pots will not protect them altogether but they are certainly easier to control. Hostas can be regarded as permanent subjects in pots and kept well fed and watered they will quickly clump up.
Grow them in loam based compost (John Innes no 3 in the UK) and feed twice a year with a controlled release fertiliser. They look particularly attractive when grouped with pots of other foliage subjects such as ferns, grasses and ivies. Gertrude Jekyll was particularly fond of Hostas in pots so this method of cultivation is nothing new!
However you grow them you will need to use some sort of slug killer or deterrent. In a well known herbaceous bible published in 1976 the author states: “a suitable poison should be spread well around the whole area just before the leaves start to appear and later, in gardens where these pests abound”.
How our attitudes have changed! This would be totally unacceptable advice in today’s more environmentally friendly world. Traditional chemical slug killers are potentially harmful to wildlife and pets so organic alternatives are desirable.
Sharp grit can be applied around the emerging shoots at the beginning of the season to deter those slimey beasties.
The biological method of control, a nematode watered onto the surrounding area from late spring onwards, is successful in control of slugs but less effective in the case of snails. It is always great news when a new alternative product appears on the market and I’m particularly excited about Slug Gone.
Vitax Slug Gone is a highly effective barrier against slugs and snails. It is actually wool pellets which you use as mulch in a 10cm, 4 inch circle around the plant you want to protect. These swell to form a felt-like mat that absorbs moisture from the slug’s foot, making it difficult for the creature to cross.
The pellets also contain abrasive particles making this natural barrier even more effective. What’s even better news is that the pellets gradually break down into the soil releasing organic nutrients. Vitax Slug Gone is soil association approved and suitable for organic gardening. I’m definitely using Slug Gone around my hostas in pots this year.
So which are the best hostas to grow?
Different varieties of Hostas abound and the number of available cultivars has exploded in recent years. Micropropagation has speeded the process of turning attractive new varieties to commercially available ones. This means of propagation means that numbers can be quickly increased from the original plant; a few years ago we were dependent on the slow process of division.
Foliage form and colour is diverse from green to blue to lime and yellow, plain self coloured leaves to those variegated with cream, white and yellow. Hosta ‘Halcyon’ is not a new variety but still an excellent blue that flowers well with spikes of palest lilac bell- shaped flowers in summer. Hosta ‘Wedgwood’ and Hosta ‘Blue Moon’ are newer varieties with similar steely glaucous foliage. Incidentally hostas with blue foliage are more resistant to slug damage.
Hosta ‘June’ is a particularly fine compact variety with elliptical green leaves edged with soft gold. The corrugated nature of the foliage is one of the attractions of this type of Hosta, the waxy surface of the leaves causing dew and rain droplets to lodge and run away like drops of mercury.
The large leaved Hosta sieboldiana ‘Elegans’ which has big, ribbed blue green leaves is one of the finest when the waxy foliage is wet. It is also particularly impressive when it produces its large spikes of lilac flowers in summer.
If you like big leaves then Hosta ‘Sum and Substance’ is a must. This has vast pale yellow-green leaves and lilac-white flowers. On rich, moist soil it will grow to vast proportions. I grow it in a pot so it doesn’t get as large but it does look stunning under the large velvet-golden leaves of Catalpa bignonioides ‘Aurea’
Of the white variegated varieties H. ‘Patriot’ is one of the finest. The leaves are broad and large; deep green broadly edged with pure white. The foliage retains its colour and condition throughout the season. This is a wonderfully striking plant for a pot that will perform year after year.
It is not only the English that Hostas appeal to. French gardens are full of them; they are much loved in America where they cope with cold winters and warm summers and combine well with annual summer colour.
Temperate gardeners everywhere recognise their appeal and importance. It’s the potential attack on their perfectly beautiful foliage that we need to guard against, conquer that with Slug Gone and Hostas are among the most rewarding plants in the garden.
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