How to Grow Solomon's Seal in Australia

Solomon's seal (Polygonatum × hybridum), in the family Asparagaceae, is a long-lived woodland perennial grown for its arching stems hung with small green-tipped white bells. It spreads slowly from fleshy underground stems and dies down to them each winter. It flowers in cool, shady corners where little else will, and most failures come from sun or from soil that dries out.

Three mistakes that matter

1. Planting in sun or a hot spot. Strong midday sun scorches the leaves, and hot, dry summers stress a plant built for cool woodland. Plant it in part to full shade, under trees or on the shaded side of a building.
2. Burying the rhizomes deep. Rhizomes (thick, creeping underground stems) planted too deep can fail and die. Lay them flat with the buds facing up, just 2.5 to 5 cm below the surface.
3. Letting the soil dry out or lie wet. Solomon's seal dislikes both dry and waterlogged soil, and the shoots suffer either way. Dig in compost or leaf mould before planting, mulch every spring, and choose a spot that drains after rain.

When to plant

Plant rhizomes while they are dormant, after the old stems have yellowed and died down, from late autumn through winter. Planted then, they settle into cold soil and send up shoots as the soil warms in spring.

A rhizome that arrives as the shoots are starting can still go in, provided the soft tips are not snapped. A potted plant in leaf can also go in during spring, at the depth it sat in its pot.

Site, soil and setup

Its parents come from temperate Europe and Asia, and it grows best in conditions that copy a woodland floor. In the cool Dandenong Ranges in Victoria, an old hill-station garden grows it in drifts beside lily of the valley.

A clump stays in place for many years, so crop rotation does not apply. Plants reach about 90 cm to 1.2 m tall.

Weed status, state by state

Container growing

The rhizomes creep sideways, so a wide pot works better than a deep one, and the ground is better still. Use a pot at least 40 cm wide and 30 cm deep, about 30 L, with drainage holes. Fill it with premium potting mix blended with compost. The store's plant is the full-sized garden hybrid; dwarf Solomon's seal (Polygonatum humile) is a smaller species it does not sell.

• Watering. Keep the mix evenly moist from the first shoots until the stems yellow, and barely moist while dormant. See watering pots in summer.
• Feeding. Water in fish and seaweed blend at 25 mL per 9 L every fortnight from the first shoots until flowering ends.
• Position. Full or part shade, with the pot itself shaded so the roots stay cool.
• Repotting. Lift and divide when the rhizomes fill the pot, as under Planting Rhizomes.

Planting Rhizomes

Solomon's seal starts from a dormant rhizome. It is pale and jointed, with round scars where old stems grew and plump buds for new shoots.

What the store sells

The store's one line is a pack of two plants of Polygonatum × hybridum, the garden Solomon's seal. It is a garden-raised cross between common Solomon's seal (Polygonatum multiflorum) and angular Solomon's seal (Polygonatum odoratum). It is the form most often grown, and the name Polygonatum multiflorum is often misapplied to it.

Planting a rhizome

1. Prepare the bed as under Site, soil and setup.
2. Space the two plants about 45 cm apart, so each clump has room to spread.
3. Lay each rhizome flat in a shallow hole, with the buds facing up.
4. Cover with 2.5 to 5 cm of soil, and no deeper.
5. Firm gently and water in with seaweed solution at 30 mL per 9 L.
6. Mark the spot, because nothing shows above ground until spring.

Dividing an established clump

A clump spreads slowly and seldom needs dividing, but it can be split every few years if it outgrows its space. Lift it while dormant in winter, or just as shoots appear in early spring, taking care not to snap the brittle new shoots. Cut the rhizome into sections about 7 cm long, each with a bud, and replant them at the depth above. See dividing perennials for the method.

Care by growth stage

Steady moisture through spring and summer decides how well the stems grow and how much the clump spreads. The plant needs little feeding beyond a yearly mulch.

Cut the stems to the base in late autumn once they have yellowed. If growth stalls in poor soil, a light dose of all-purpose controlled release granular (NPK around 14-5-10) scratched in each spring can help.

Companion planting

Pair Solomon's seal with other plants that like cool, moist shade, leaving room for its slowly spreading rhizomes.

Grows well with

• Ferns, whose fronds fill the spaces between the upright stems.
• Hostas and hellebores, shade lovers that want the same rich, moist soil.
• Aquilegia, which flowers in spring in the same dappled light.
• Daffodils, whose early flowers fill the bed while the shoots are still emerging.

Keep apart

• Mint and other vigorous spreaders, which invade the clump and compete for water.
• Vegie beds and paths that are dug or walked on, which snap the shoots and damage the rhizomes.

Harvesting Blooms

Cut stems for the vase from late spring into early summer, when most of the bells along the stem have opened.

• Leave most stems on the plant, because the leaves feed the rhizome for next year.
• Cut in the cool of early morning, with clean secateurs.
• Cut at the base of the stem and stand it straight in deep water.
• Take few or no stems in the first year, while the plant settles.

The foliage stays good from early spring to autumn, so the stems also work as cut foliage after the flowers fade. Strip off any berries before bringing stems indoors, and stand the vase out of reach of children and pets.

Common problems

No shoots in spring. Shoots appear only as the soil warms, so wait. A rhizome that is soft and brown when uncovered has rotted in wet soil; replant any firm sections on a raised bed.

Brown, crisp leaf edges. Sun or dry soil scorches the leaves; move the clump to deeper shade and water through dry spells.

Leaves fading in summer. Heat can make the leaves fade before the stems die down in autumn; keep the soil over the rhizomes moist and shoots return in spring.

Few or no flowers. A young clump can take two to five years to fill out and often flowers lightly meanwhile; give it time and a yearly compost mulch.

Pests and diseases

Solomon's seal has few pest or disease problems, and most damage comes from snails and slugs on the emerging shoots.

Garden snail (Cornu aspersum). The common garden snail of urban Australia chews holes in the soft young shoots and leaves as they unfurl in spring. Hand-pick on damp evenings. If bait is needed, use an iron-based one registered for home gardens, follow its label and scatter it thinly, never in heaps. Keep the packet where dogs cannot reach it. Read more

Grey field slug (Deroceras reticulatum). A fawn to grey slug with netted dark markings, up to 50 mm long, common in the wetter south. It feeds at night on the new shoots. Search with a torch after rain, and set tiles or flowerpot bases as traps to gather them. Read more

Prevention first

• Clear boards, pots and loose debris from beside the clump, where slugs shelter by day.
• Check new shoots on damp nights from late winter.
• Keep mulch a hand's width clear of the emerging shoots.
• Take the cut stems off the bed in late autumn, so slugs cannot shelter under them.

Tips

1. In a garden where young children play, snip off the green berries as they form and leave the leafy stems standing.
2. Leave fallen tree leaves around the clump, where they act as a natural mulch and build humus.
3. Once its roots are established, a clump copes with dry shade among tree roots, but water it well through its first summers.

Due to quarantine restrictions and our shipping policy, we cannot send Solomon's seal plants to Western Australia or Tasmania.