How to Take Care of Hosta Plants: Water, Feeding, Pests and Diseases
Hostas need little care once they are in the right place: part shade, moist but well-drained soil, about an inch of water a week in dry spells, a light feed in spring and a thin layer of mulch. Most of the real work is protecting the leaves from slugs and deer and keeping disease out. The Royal Horticultural Society (RHS) sums it up: “All hostas give their best in moist soil in partial shade, whether in the ground or a container” (RHS).
Hosta care at a glance
| When | What to do | Why |
|---|---|---|
| Early spring, as growth starts | Apply a slow-release fertilizer if the soil needs it | Feeds the new flush without forcing soft growth (UNL Extension) |
| Spring, as shoots emerge | Divide or move overgrown clumps | Iowa State calls spring, as leaves begin to emerge, the best time (Iowa State) |
| Early summer | Spread about 1 in of loose organic mulch | Holds moisture and suppresses weeds (UNL Extension) |
| Summer | Water about 1 in per week when rain does not; check for slugs at night | Drought causes leaf-tip dieback and stunted growth (UNL Extension); amount per Clemson HGIC |
| Fall, after a hard freeze | Cut back dead foliage; bin it if it was diseased | Timing per Iowa State; cutting back also reduces future slugs (University of Illinois Extension) |
| After the ground freezes | Winter mulch over new plantings only | Prevents frost heaving (University of Illinois Extension) |
Where to plant
Pick part shade with shelter from afternoon sun. The University of Nebraska–Lincoln (UNL) Extension notes that hostas generally do best where they get only morning sun, and that the site needs good air circulation; hostas planted in open, sunny spots beyond their tolerance get burned or bleached leaves (UNL Extension). Yellow-leaved hostas take more light, and blue ones keep their colour best in lighter shade (RHS). If your only space is sunny, see hostas for sun; for deep shade, see hostas for shade.
The RHS recommends fertile soil, including heavy clay, improved with garden compost or well-rotted manure. On drier sites it suggests thicker-leaved cultivars (RHS).
Watering
- How much: Clemson’s Home & Garden Information Center says hostas “will need an inch or more of water per week if not supplied by rains”, and more in hot weather or where tree roots compete (Clemson HGIC). The RHS advises keeping border soil moist to about 6 in deep in dry spells. Plants in containers dry out quickly and need regular watering in summer (RHS).
- How: water the soil, not the leaves. UNL Extension prefers drip tubing or soaker hoses to overhead sprinklers, because dry foliage reduces disease problems and keeps blue leaves bluer (UNL Extension).
- When: water in the morning so the mulch surface dries before evening (UNL Extension). Damp mulch at night favours slugs.
The old idea that you must water daily, or that sun “burns” wet leaves, is not supported by the sources we checked. Water deeply when the soil is dry, not on a fixed daily schedule.
Feeding
Hostas need far less fertilizer than most people give them. UNL Extension warns that too much nitrogen makes soft foliage that wilts easily and is prone to leaf diseases, and that it can dull the variegation. If you feed, use a slow-release fertilizer just as growth begins in spring (UNL Extension). Clemson HGIC gives the same advice and warns against excessive rates (Clemson HGIC). In good soil, the RHS says an annual mulch of compost or well-rotted manure is all the feeding needed. For pots, it suggests a liquid feed once a month during growth (RHS). For product types, see choosing a fertilizer for hostas.
Mulch
In early summer, UNL Extension recommends about 1 in of loose organic mulch to suppress weeds, reduce water loss and lessen soil compaction. A thicker layer is likely to encourage slugs, so occasionally rake the mulch to let air move (UNL Extension).
Cutting back and dividing
Do not cut hostas back at the first light frost. Iowa State University Extension advises cutting perennials back in fall after a hard freeze has killed the foliage (Iowa State). Remove spent flower stalks whenever they look untidy. The full fall routine is in what to do with hostas in the fall.
Divide clumps that have grown too big or have a dead centre. UNL Extension gives two windows: spring after the shoots emerge, or late summer after temperatures drop and flowering has ended. Leave the crown just above soil level and do not bury it (UNL Extension). Step-by-step instructions are in how to divide and transplant hostas.
Slugs and snails
Slugs are the main hosta pest. They chew ragged holes and leave silvery trails, feeding at night and in cool weather. Leaves near the ground and thin-leaved cultivars suffer most (UNL Extension).
| Method | What the evidence says |
|---|---|
| Copper tape, eggshells, sharp grit | An RHS study in a garden-realistic setting found no reduction in slug damage from these barriers (RHS) |
| Hand-picking at night | Often effective for smaller beds (UNL Extension) |
| Beer traps, boards, wet burlap | Collect large numbers for disposal (UNL Extension) |
| Less mulch and leaf litter; morning watering | Removes daytime hiding places (UNL Extension) |
| Nematode biological control | Specific to molluscs, watered into the soil (RHS) |
| Metaldehyde bait | UNL calls it the most effective control (UNL Extension), but it is very toxic to dogs and other animals that eat it (NPIC) |
| Iron phosphate bait | Much less toxic to dogs, but slower: up to seven days (NPIC) |
If you use any bait, the National Pesticide Information Center (NPIC) advises using small amounts spread evenly, not piles. Store it away from pets and follow the label (NPIC). The RHS cautions that pellets, even organic ones, can harm garden wildlife (RHS). Salt is not a recommended control in any of the sources we used. For product types, see slug and deer deterrents.
Deer
Deer eat hosta leaves and leaf stalks (Clemson HGIC). The Hosta Helper, the American Hosta Society’s reference site, lists these options (The Hosta Helper):
- Fencing is the most reliable: about 10 ft tall and leaning outward, or a solid fence about 6 ft tall with shrubs on both sides to block the deer’s view.
- Repellents make leaves taste or smell bad, but they wash off with rain or irrigation and must be reapplied. University of Maryland Extension also recommends changing repellents between applications, because deer get used to them (UMD Extension).
- Scare devices such as motion-activated sprinklers work only if you move them every week or so.
- Dogs kept outside at night, within an invisible fence, will chase deer off. Human hair is less effective where deer are used to people.
For repellent types and how they compare, see best deer repellents.
Voles
Voles damage hosta root systems (Clemson HGIC). University of Maryland Extension recommends snap-type mouse traps baited with apple, set in the runways. It also advises clearing weeds and litter, and not piling mulch against plants (UMD Extension). North Carolina State Extension suggests setting the trap across the runway at the exit hole. Cover it with a clay pot to protect pets and birds, and check it daily (NC State Extension). Maryland Extension uses pea gravel around trunks against winter vole damage (UMD Extension). Some gardeners use gravel in hosta planting holes for the same reason, but we found no study of this on hostas.
Diseases
| Problem | Signs | What to do |
|---|---|---|
| Anthracnose | Irregular white-to-tan spots with brown borders; centres fall out. Worse in warm, wet weather | Keep foliage dry; fungicides labelled for hostas if it recurs (UNL Extension) |
| Crown rot | Lower leaves yellow and brown, then the whole plant collapses; white threads and mustard-seed-sized bodies at the base | Remove the plant and the surrounding soil to 8 in deep (UNL Extension) |
| Hosta virus X (HVX) | Mottling or “ink” streaks between veins | No cure. Dig out and dispose of the plant (Clemson HGIC); it spreads on sap-covered tools (UNL Extension) |
| Foliar nematodes | Yellowing then browning between the veins | See hosta diseases (Clemson HGIC) |
Crown rot arrives on infected plants and soil, so inspect new plants and their potting mix before planting (UNL Extension). More detail is in hosta diseases.
Related guides
- What to do with hostas in the fall
- How to divide and transplant hostas
- Hosta diseases
- Hostas for shade
- Companion plants for hostas
- Are hostas poisonous?
Sources
- Royal Horticultural Society — Hostas: growing guide
- Royal Horticultural Society — Slugs and snails
- University of Nebraska–Lincoln Extension — Hostas (NebGuide G1683)
- Clemson Cooperative Extension, Home & Garden Information Center — Hosta
- Iowa State University Extension — How should I prepare my perennial beds for winter?
- Iowa State University Extension — When is the best time to divide hostas?
- University of Illinois Extension — Take care of hostas before going into winter
- National Pesticide Information Center — Snail and slug baits
- The Hosta Helper (American Hosta Society) — Deer
- University of Maryland Extension — Voles
- University of Maryland Extension — Using commercial deer repellents
- NC State Extension, Henderson County — Trapping voles in the landscape