Hostas are one of the best foliage plants for light to medium shade and are deservedly popular. These resilient and easy-to-grow plants are available in a wide range of leaf colours, sizes and shapes, and are also valued for their flowers, which are often fragrant. Both flowers and foliage are as favoured by the flower arranger as the gardener.
Hostas will grow on any fertile, moisture-retentive garden soil, but thin sands and heavy clays are best improved before planting. Liming to moderate the pH to 6.5-7.3 is advisable where soils are acid. More soil moisture is required where shade is light, so incorporate additional organic matter, such as garden compost or leafmould.
Plants take about five years to reach full size and then need no further disturbance for many years.
Moisture is essential and hostas will fail to thrive where the soil remains dry for long periods. Watering may be required, but mulching with well-rotted organic matter is especially helpful in maintaining ideal moist, fertile conditions. An annual dressing in late winter of general–purpose fertiliser may be needed in poor soils in the same way that other herbaceous plants are treated.
Garden hostas are extremely hardy and thrive in cold regions coming from China, Japan and Korea. They are particularly popular in North America.
Hosta can be grown in containers using any good general-purpose potting compost, including soil-based (John Innes No 2 or No 3) or peat-free. Container-grown hostas must be carefully watered to ensure they don't dry out. Likewise, liquid feeding is likely to be required every month, using a general-purpose liquid fertiliser. When the pots is filled with roots and the crown has become congested, repot into a larger container or split and replant just a few sections into the same size pot.
Pruning and training
Very little pruning and training is required. Hosta foliage dies down in winter and is then consigned to the compost bin. Flower stalks are cut out when no longer attractive.
Hostas are very easily increased by division between autumn until mid-spring.
- Lift the clump with a fork, or tip out of containers taking care not to damage the growing points
- Place clump on a board or plastic sheet on the border or lawn
- Those plants with tough, fibrous roots can be divided with a sharp spade or an old kitchen knife cutting between the shoots and slicing the clump in two
- If feasible divide large clumps into a number of sections each containing five or six shoots
- Plants with loose, fleshy roots can be teased apart buy hand or by levering with two forks placed back-to-back
- Ensure the divisions are replanted at their original depth in the ground, with the shoots just poking through the soil surface
- Water the plants and apply a granular fertiliser a rates recommended by the manufacturer. A slight depression around the plant can be left to ease watering
Topping is refinement of division where the crown is uncovered in spring and small cuts made in pairs at right angles. The cuts are dusted with hormone rooting powder and held open with a toothpick. Soil is replaced and, all being well, numerous new plants will form where the wounds have been made. By the following spring these can be separated and replanted.
Hostas can be raised from seeds sown in autumn or in early spring but unless they are species types, they won’t come true from seed.
Hosta ‘Halcyon’ AGM: Heart-shaped, grey-blue leaves on a plant to 20cm (8in), lavender-grey flowers.
Hosta ‘Sum and Substance’ AGM: Very large and dramatic golden leaves up to 1.2m (4ft) long, white flowers.
Hosta ‘Shade Fanfare’ AGM: Medium sized leaved up to 50cm (20in) long, white leaf margins, green centres, lavender flowers.
Hosta ‘Golden Tiara’ AGM: Small to medium size plant with numerous small light green, yellow margined leaves to 15cm (6in).
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Hosta 'Sum and Substance'
Hosta 'Golden Tiara'
Slugs and snails are the bane to anyone who grows hostas as they can strip the foliage early in the season. Growing plants in containers may help a little with control, though vine weevil can be more problematic in pots.
Crown rot, caused by fungal or bacterial diseases, occasionally occurs – particularly where soil is prone to waterlogging. Replacement in a new site is the only remedy, unless the soil can be changed for fresh material and drainage improved, if necessary, before replanting in the same spot. Virus diseases may also infect plants that must then be discarded.
Brown and scorched leaves are common where soils get dry or where there is excessive sun or, most damagingly, both combined. Replanting in a shadier place is the best long-term remedy.