Sedum palmeri

Plant Profile & Key Characteristics

Overview: Palmer’s sedum (Sedum palmeri) is a low, evergreen, drought-tolerant succulent groundcover, 10-70 cm (4-28 in) tall, grown for its fleshy foliage and star-like flower clusters. This slow-growing perennial is used mainly as ornamental groundcover in rock gardens, containers and green roofs (hardiness zone 7-10a (10b with care)).

Quick Specifications

Specification	Attribute
Plant Type / Life Cycle	Perennial (evergreen succulent, groundcover)
Foliage Type	Evergreen (fleshy, succulent)
Mature Size	10-70 cm (4-28 in), spreading
Growth Rate	Slow
Root System	Shallow, fibrous
Toxicity	Toxic to cats
Hardiness	USDA zone 7-10a (10b with care)

Growth Form & Structure

• Height & Spread: Reaches 10-70 cm (4-28 in); a low, drought-tolerant groundcover that also does well in shallow, wide containers and can be grown indoors as a houseplant.
• Growth Habit & Form: Low, spreading, mat-forming succulent with trailing or creeping stems that root as they spread, forming a dense groundcover.

Anatomy & Physical Features

• Leaves & Foliage: Light-green fleshy leaves (edges sometimes red-tinged) arranged in loose rosettes.
• Flower Characteristics: Bright yellow, star-like flowers in clusters at the branch tips.

Primary Uses & Landscape Value

• Functional & Ornamental Roles: Ornamental groundcover, rock-garden, green-roof and container plant, houseplant and cascading container succulent.

Care Guide: Planting, Soil & Watering

Overview: Sedum palmeri (Palmer’s Sedum) is a hardy, drought-tolerant succulent that thrives in bright light and gritty, sharply draining soil. It stores water in its fleshy leaves, so it needs only occasional watering and quickly rots in heavy, wet ground.

Quick Care Requirements

Requirement	Ideal Condition
Planting Season	Spring in zones 7–8; spring to summer in zones 9–10a; spring to autumn zone 10b
Growth Rate	Slow
Soil Type	Light, sandy, well-draining soil — a cactus/succulent mix or soil opened up with grit
Water Need	Low — let the soil dry out completely between waterings

Planting & Establishment

• Best Planting Season: Set out plants in the warmth of spring so the roots settle before winter; in the mildest zones the window stretches further (spring in zones 7–8; spring to summer in zones 9–10a; spring to autumn zone 10b). In cold-winter areas grow it in containers that can be moved under cover.
• How to Plant:
  • Hole Preparation: Dig a shallow hole just wide and deep enough for the small root ball — these succulents are shallow-rooted and resent sitting in a deep, water-holding pocket.
  • Soil Amendments: Mix coarse sand, grit or perlite into the bed to sharpen drainage; aim for a lean, airy soil rather than a rich, moisture-retentive one.
  • Planting Depth: Set the crown level with the soil surface so the fleshy stems and leaves rest on top — never bury them, which invites rot.
• Growth Speed & Expectations: Expect slow growth; as a spreading groundcover it knits together steadily into a low mat rather than shooting upward.

Soil, Watering & Drainage Care

• Soil Mix & Drainage Needs: Give it a light, well-aerated mix; in pots use a shallow, wide container of free-draining cactus/succulent soil with ample drainage holes. Waterlogged soil is the single biggest threat, quickly rotting the roots and stems.
• Watering Schedule & Technique:
  • Young / Newly Planted: Water lightly after planting and then only once the soil has dried, just enough to help new roots settle — overwatering now is the main cause of failure.
  • Established: Water deeply but infrequently, always letting the soil dry out completely first; established plants shrug off real drought.
  • Seasonal Adjustments: Cut watering back sharply in winter while the plant rests, and water a little more often only during prolonged summer heat.

Climate, Light & Hardiness

Sedum palmeri is a versatile succulent that grows across tropical, Mediterranean, subtropical, desert, and temperate climates, and also works well as a houseplant. It adapts to light ranging from full sun to full shade, and per the site data it is comparatively cold-tolerant for the genus, hardy into zone 7.

Quick Climate Specifications

Climate Zones	Tropical, Mediterranean, Subtropical, Desert, Temperate
USDA Hardiness Zones	Approximately 7–10a, with 10b achievable with extra care
Optimal Temp Range	Approximately 15–27°C (59–80°F)
Cold Damage Begins	Tender growth can be marked as temperatures approach freezing
Approx. Survival Minimum	In the zone-7 portion of its range, established plants in a sheltered, well-drained site can briefly tolerate freezing conditions, though cold tolerance varies with exposure and plant maturity
Frost Tolerance	Moderate (varies by site and maturity)
Light Conditions	Full Sun / Half Shade / Full Shade

Sunlight & Light Exposure

Optimal Light Setup

Full sun to half shade gives the most compact rosettes and best color, especially on red-edged cultivars; it also tolerates full shade, which suits indoor growing.

Direct Sun Requirement

Direct sun is beneficial but not mandatory - its broad light tolerance works for sunny beds or bright indoor rooms.

Shade & Heat Management

Its shade tolerance offers flexibility in hot-summer climates; no special heat management is generally needed.

Best Exposure/Orientation

A sunny to lightly shaded outdoor bed, or a bright windowsill when grown indoors.

Temperature Extremes & Hardiness

USDA Hardiness & Regional Limits

The site data places it in hardiness zone 7–10a, extending to 10b with extra care - a comparatively cold-tolerant range for this genus, though performance at the cold end likely depends on drainage and shelter.

Cold Damage & Winter Protection

Sharp drainage and a sheltered site help it handle winter cold; young or newly rooted plants are more cold-sensitive than mature clumps, and container specimens benefit from winter protection in the coldest part of the range.

Frost Sensitivity

Moderate for a soft succulent, but frost can still damage exposed foliage, especially on younger growth.

Extreme Heat Tolerance

Good - as a drought-tolerant succulent it handles warm-climate summer heat well.

Wind, Humidity & Microclimate

Humidity Preferences

Prefers drier air over constantly humid conditions, which increase the risk of rot.

Dry-Air Tolerance

High - well suited to arid and semi-arid climates and typical indoor room air.

Wind Tolerance

Moderate; its low, spreading rosette habit copes reasonably well in open sites.

Rainfall & Seasonal Moisture

Well-drained, sandy soil (as the site recommends) is important in wetter climates to prevent waterlogging and rot.

Microclimate Recommendations

A sunny, sharply drained, sheltered site suits it best in the cooler part of its range; container culture allows moving plants under cover during hard freezes.

Growing in Pots, Balconies & Indoors

Sedum palmeri is a compact succulent that makes an easy, good-looking houseplant or patio-pot plant. It stays small, stores its own water and asks mainly for light and sharp drainage. Indoors it needs your brightest window – in a room’s weaker light it stretches and softens.

Quick Details

• Container Size: From about 5-8 L (bigger is fine); a wide, shallow pot roughly 10-15 cm deep and 70-150% wider than the root ball
• Indoor Suitability: A good little houseplant in a bright spot
• Best Spot: Bright light to full sun
• Soil & Drainage: Free-draining cactus/gritty mix – drainage is everything
• Watering in Pots: Water only when the mix has dried out; pots must never stay soggy

Indoors & On the Windowsill

• As a houseplant: Yes – it grows happily indoors given enough light. Stand it at your brightest window (south or west facing) so growth stays tight and well coloured rather than pale and drawn.
• Windowsill growing: Its compact size suits a sunny sill; turn the pot now and then for even growth, and water only when the mix is dry.
• Overwintering: In cold climates a pot lets you bring it indoors to a bright, cool, frost-free spot over winter.

On a Balcony or Patio

• Light, heat & wind: Give it the brightest spot you have; walls and railings throw back a lot of heat and pots dry fast, so check the mix often in warm weather. Move tender succulents under cover before frost.
• Practicalities: Raise the pot on feet so water drains away freely and does not pool on the balcony floor.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: Use a pot with strong drainage holes and skip a standing saucer of water – wet feet are the fastest way to rot a succulent. Terracotta breathes and dries quickly, which suits it well; glazed or plastic holds moisture longer, so water more sparingly.
• Potting mix: A free-draining cactus/succulent mix, or a standard mix opened up with plenty of perlite, pumice or coarse sand; a layer of gravel, lava rock or pebbles in the base helps water clear.
• Feeding: Potted plants use up their soil, so feed lightly once or twice through the growing season with a dilute cactus or balanced feed – far less than a leafy houseplant needs.
• Refreshing the mix: After a couple of years the mix stops draining freely – tip the plant out, trim any tired roots and repot into fresh gritty mix.

Grower’s Container Tip

• Wide, shallow and root-pruned: Choose a container about 70-150% wider than the root ball but only 10-15 cm deep – wide and shallow beats deep. To keep the plant compact, lift it every so often and trim the roots so fresh ones regrow. Drainage matters most: use cactus mix or sandy soil with gravel, lava rock or pebbles, and renew the mix once it stops draining after a few years.

Fertilizing & Feeding

A light feeder: the largest-growing sedum in this group, Palmer’s Sedum still does best on lean soil and an occasional light feeding through the growing season, with none needed once growth slows.

Quick Fertilizing Specs

Feeding Level	Light feeder
Main Nutrient Priority	A dilute, balanced feed applied sparingly to support steady rosette growth and red-pink blooming without excess soft growth
Best Feeding Period	During the warm active growing season
Organic Options	A little compost worked into a light, sandy, well-ventilated soil
Reduce/Stop Feeding	Ease off as growth slows going into cooler weather
Micronutrients	Usually met by a complete fertilizer; correct only a diagnosed issue
Soil pH	Tolerates a wide range in a light, sandy, well-drained soil

Feeding by Growth Stage

Warm-season growth and bloom support

Support rosette growth and red-pink flowering during the warm season without pushing excess soft growth on this larger-growing sedum.

Nutrient direction	A light, diluted balanced feed, used sparingly, supports growth and bloom without overfeeding this still-modest succulent.
Timing	During the warm growing season, avoiding the coldest months.
Frequency	Light, infrequent feeding through active growth is enough; being the larger-growing sedum here does not mean it needs heavier feeding.
Fertilizer types	A dilute, balanced liquid fertilizer, used sparingly, A little compost worked into a light, sandy, well-drained soil
Precautions	Feed sparingly; overfeeding produces soft, floppy rosettes and raises the risk of rot in damp soil, without improving bloom.

Cooler-season rest

Let this slow-growing succulent rest through the cooler part of the year without pushing tender new growth.

Nutrient direction	None – withhold fertilizer while growth is slow or stopped.
Timing	During the cooler part of the year, when growth naturally slows.
Frequency	No feeding at this stage; resume only once active growth returns.
Fertilizer types	No feeding at this stage; do not fertilize until active growth resumes.
Precautions	Withhold fertilizer now; feeding a resting plant wastes nutrients and adds unnecessary stress heading into cooler weather.

Nutrient Deficiency Signs & Corrections

Leaf color looks pale or washed out and growth, already slow for this succulent, becomes even slower over a full season.

Possible causes	low available nitrogen in lean, well-drained soil that has gone unfed for a long time, nutrients leaching through fast-draining, sandy or gritty soil, general root stress from poor drainage or a waterlogged spot
Appears first on	older, lower leaves
What to check	how long since any feeding or soil amendment, drainage and soil texture around the root zone, overall plant vigor and leaf color
Possible correction	Apply a dilute, balanced or low-nitrogen fertilizer during the next active growing period and consider a light organic matter amendment.

Leaf tips or margins brown and look scorched, especially on a container-grown plant.

Possible causes	fertilizer salt buildup in a container with limited soil volume, feeding too often or too concentrated for this light-feeding succulent, poor drainage concentrating salts near the roots
Appears first on	leaf tips and margins
What to check	recent feeding frequency and strength, container or soil drainage and any visible salt crust on the surface, whether the plant is in-ground or containerized
Possible correction	Ease off feeding, water thoroughly to move accumulated salts through the drainage, then resume lighter feeding.

Leaf margins or tips show scorch-like browning and stems look less sturdy than usual with reduced flowering vigor.

Possible causes	potassium deficiency in soil that rarely receives balanced feeding, nutrient leaching from frequent watering in a fast-draining mix, root stress from a compacted or exhausted potting medium
Appears first on	older leaf margins and tips
What to check	recent feeding history and balance of the fertilizer used, age and condition of the soil or potting mix, watering frequency relative to drainage
Possible correction	Switch to a balanced fertilizer that includes potassium during the next active growing period, and refresh an old, exhausted mix.

Pruning, Training & Seasonal Maintenance

Sedum palmeri is one of the more genuinely trailing/cascading Sedums in this group — its rosette-tipped stems can reach 10–70cm and cascade over a pot or wall rather than staying in a tight low mound. Pruning tolerance is still low, but trimming here does real work: pinching and shortening trailing stems keeps the plant dense instead of bare-stemmed near the base, which is the main way this species loses its looks over time. Its own facts point to winter as the better pruning window.

Quick Pruning & Maintenance Specs

Pruning Tolerance	Low–Moderate
Primary Pruning Window	Winter
Secondary Maintenance Window	Any time, for spent blooms or damaged growth
Typical Frequency	One shaping/grooming pass a year, more often in a hanging basket to control trailing length
Main Objective	Remove spent bloom stems, pinch tips for density, shorten overly long bare-based trailers
Young Plant Priority	Leave undisturbed while establishing
Mature Plant Priority	Pinch stem tips to prevent bare-based legginess; cut back and re-root an overly long trailing stem rather than letting it go bald at the base
Best Tool Type	Small precision snips
Avoid Heavy Pruning During	Summer heat/drought stress; right after transplanting

Pruning by Plant Age & Size

Newly Established

No pruning; remove only damaged leaves from transplant handling.

Young / Formative

No formal training system, but pinching stem tips early encourages branching from the base, which is what keeps a trailing Sedum full instead of a single bare runner.

Mature / Established

As trailing stems lengthen and lose lower leaves (normal as they age), shorten the worst offenders back toward the base and use the cut tips as new cuttings to fill in bare spots — effectively renewing the display without hard-pruning the whole plant.

Structural Pruning & Training

Trailing-stem length and base density are the two real controls here: pinch young tips for branching, and cut back stems that have gone bare-based and leggy so the plant regrows fuller from a lower point.

Special Growth to Remove

• Spent red-pink flower clusters once bloom fades — cut at the stalk base.
• Bare, leafless sections of older trailing stems — shorten back to leafy growth.
• Shriveled lower leaves as stems lengthen.

Container & Small-Space Pruning

Commonly grown in hanging baskets or trailing over a pot edge, where trailing length needs more active control than in-ground groundcover use; trim to the container’s edge rather than letting stems drag and self-shade. Root trimming at repotting (per the plant’s own container guidance) controls overall size.

Tools

Precision snips only — all cuts are on thin, fleshy trailing stems.

Tool Hygiene & Disease Risk

Routine. Main pest pressure is slugs and snails, not disease; clean sharp blades avoid crushing.

Cut Placement & Technique

Cut at a leaf node or stem base rather than mid-leaf; the plant’s own propagation notes describe cutting at the leaf/stem base for the cleanest heal, and the same cuts serve as propagation material.

Heavy Pruning & Rejuvenation

Whole-plant hard pruning is not really suited to this species; instead renew a badly bare-based specimen gradually, one overly long stem at a time, or start fresh from cuttings.

Post-Pruning Care

Let cut ends callus a day or two before contacting soil, per the plant’s own propagation guidance, and avoid heavy watering right after cutting.

Common Pruning Mistakes

• Letting trailing stems go bare-based for years before addressing it, instead of pinching early.
• Cutting mid-leaf instead of at a node/base.
• Watering heavily right after a fresh cut.

When Not to Prune

Avoid during summer heat/drought stress and immediately after transplanting.

Recommended Tools (by task)

Task	Tool Category	Why
Pinching tips, removing spent blooms, shortening trailing stems on any age plant	precision_snips	Every cut is on thin, fleshy trailing stems; a small sharp blade gives a clean cut without crushing

Propagation Guide

Sedum palmeri is a succulent and must not receive palm propagation instructions. It can be propagated vegetatively from healthy stem cuttings or by separating established rooted sections. Seed can also be used, but it is slower than vegetative propagation.

Quick Propagation Specs

Best Practical Method	Stem cuttings
Division	Possible from established rooted sections
Seed	Possible

Stem Cuttings

Take a healthy stem section with viable nodes, allow the cut surface to dry briefly if needed, and place it in a clean, very well-drained succulent medium. Keep the medium only lightly moist while roots form.

Division

Where an established plant has formed separately rooted stems or sections, separate them carefully and replant them in well-drained soil or container mix.

Aftercare

Protect newly propagated plants from prolonged wet conditions and increase light gradually after rooting.

Bloom & Flower Guide

Quick Details

• Bloom Season: Summer (in mild climates it can flower from late winter into spring)
• Flower Appearance: Small, bright yellow, star-shaped flowers in arching clusters at the stem tips
• Edibility: Ornamental – grown for its rosettes and flowers, not eaten

Detailed Blooming Overview

Palmer’s sedum is one of the more free-flowering stonecrops, carrying showy clusters of bright yellow, star-shaped flowers at the ends of arching stems. The blooms open generously on a well-established, sun-grown plant and are a strong draw for bees and other small pollinators.

Flower Characteristics

• Small, bright yellow, star-shaped flowers
• Carried in loose, arching clusters at the tips of the stems
• Nectar-rich and attractive to bees and hoverflies

Bloom Care & Thinning

• Encouraging bloom: Full sun and a cool, dry winter rest bring on the heaviest flowering.
• Aftercare: Trim the spent flower stems once they fade to keep the plant tidy.
• Pollination: Insect-pollinated – mainly bees.

Pests, Diseases & Troubleshooting

Overview: Palmer’s sedum is a semi-hardy Mexican cliff species that trails from walls and pots and smothers itself in golden-yellow spring flowers. Like all stonecrops, Sedum palmeri is far more often harmed by cultivation mistakes-above all overwatering-than by any pest. The insects it does attract (mealybugs and aphids under cover, slugs and snails outdoors) are few and easily managed by hand or with gentle organic sprays. Grow it hard in sharply drained gritty soil with strong light, water only when the soil is dry, and most problems never begin.

Quick Troubleshooting Overview

Issue / Pest	Main Symptom	Primary Solution
Mealybugs	White cottony tufts tucked into leaf axils and rosette centres, sticky honeydew and sooty mould	Dab with alcohol, rinse, then insecticidal soap or neem
Aphids	Clusters of soft green/black insects on new growth and flower stems, distortion and sticky sap	Blast with water, insecticidal soap, encourage ladybirds
Slugs & snails	Ragged holes and slime trails over the fleshy leaves, worst in damp weather	Hand-pick after dark, grit/copper barriers, iron-phosphate bait
Root & stem rot	Blackened, mushy, translucent stems that collapse at the base	Withhold water, improve drainage, cut back to firm tissue and re-root
Etiolation	Stems stretch pale and floppy with wide gaps between leaves	Move to much brighter light; behead and re-root compact tips
Sedum rust	Rusty-orange pustules on undersides of leaves and stems	Remove affected growth, improve airflow, sulphur if severe

Common Pests & Management

• Mealybugs (Planococcus citri / Pseudococcus spp.):
  • Symptoms: Slow-moving, soft insects coated in white waxy fluff, hiding deep in leaf axils, rosette centres and among trailing stems. They excrete sticky honeydew that turns black with sooty mould; heavy infestations stunt and yellow the plant. Do not mistake the cottony masses for the natural waxy bloom on the leaves.
  • Prevention & Control: Inspect new plants before introducing them and isolate any that are infested. Touch each colony with a cotton bud dipped in isopropyl alcohol, then rinse. For wider outbreaks spray insecticidal soap or neem oil, wetting the hidden crevices, and repeat weekly until clear. A bad potted infestation is best cured by unpotting, washing the roots (root mealybugs hide there too) and repotting into fresh gritty mix.
• Aphids (Aphis sedi and other Aphis spp.):
  • Symptoms: Dense clusters of soft green, grey or black insects on tender new shoots and especially on the flower stalks, causing curling and sticky honeydew. Aphis sedi is the stonecrop specialist and swarms flowering heads.
  • Prevention & Control: Knock them off with a firm jet of water, repeated every few days. Encourage ladybirds, lacewings and hoverflies, which clear light infestations on their own. If they persist, an insecticidal soap or a light neem spray in the cool of evening works well; avoid spraying open flowers to protect pollinators.
• Slugs & Snails (Deroceras reticulatum, Cornu aspersum):
  • Symptoms: Irregular holes chewed in the plump leaves and stems, tender new mat growth grazed away, and tell-tale silvery slime trails; damage appears overnight and in wet spells.
  • Prevention & Control: Keep the crown dry and the surrounding ground open. Hand-pick after dark by torchlight, set beer traps, and ring vulnerable plants with sharp grit, crushed shell or copper tape. Where pressure is high, scatter iron-phosphate pellets, which are safe around pets and wildlife.
• Vine weevil (Otiorhynchus sulcatus):
  • Symptoms: Adults notch neat bites from leaf margins at night; the real damage is done below ground by fat, legless, C-shaped white grubs that devour roots, causing sudden wilting and collapse of an otherwise healthy plant-most serious in containers.
  • Prevention & Control: Check the rootball of new plants. Water in a drench of beneficial nematodes (Steinernema/Heterorhabditis) into moist, warm compost to kill the grubs; repot survivors into fresh mix and remove any adults found at night.

Diseases & Fungal Issues

• Crown, stem & root rot (Pythium, Phytophthora, Fusarium, Rhizoctonia):
  • Symptoms: By far the commonest killer of stonecrops. Stems and the base of the plant turn black, soft, translucent and foul-smelling, then collapse; roots are brown and mushy. It follows soggy soil, buried crowns or cold wet conditions.
  • Treatment & Management: Prevention is everything-use a fast-draining gritty mix, pots with drainage holes, and water only when dry, never letting the plant sit wet. If rot appears, cut cleanly back into firm green tissue, let the cutting callus, and re-root it; discard badly rotted plants and the contaminated soil.
• Botrytis / grey mould (Botrytis cinerea):
  • Symptoms: Fuzzy grey-brown mould on leaves, stems and faded flowers in cool, damp, crowded conditions; affected tissue rots and drops.
  • Treatment & Management: Improve air movement, avoid overhead watering, and remove dead leaves and spent flower heads promptly. Thin congested growth; a copper or biological fungicide helps only if the underlying damp is corrected.
• Sedum rust (Puccinia spp.):
  • Symptoms: Powdery rusty-orange to brown pustules on the undersides of leaves and on stems, with yellow blotches above; heavy attacks weaken and disfigure the plant.
  • Treatment & Management: Pick off and destroy infected leaves at first sign, space plants for good airflow and keep foliage dry. Persistent cases respond to a sulphur or other organic fungicide applied to protect new growth.
• Powdery mildew (Erysiphe/Golovinomyces spp.):
  • Symptoms: A less frequent, white powdery film on leaves and stems in warm, humid, still air, sometimes distorting new growth.
  • Treatment & Management: Increase spacing and airflow, remove affected parts, and treat if needed with a potassium-bicarbonate or sulphur spray.

Growing Difficulties & Abiotic Problems

• Overwatering & waterlogging:
  • Cause & Symptoms: The single most common problem-leaves and stems turn yellow, translucent, soft and mushy, and the plant rots from the base. Caused by too-frequent watering, water-retentive soil or pots without drainage.
  • Correction Strategy: Let the soil dry fully between waterings, switch to a gritty free-draining mix, and always use a pot that drains. When in doubt, water less-a stonecrop recovers from drought far more readily than from rot.
• Etiolation (stretching for light):
  • Cause & Symptoms: In too little light the stems elongate, grow pale, and the leaves space out and point down, losing the tight compact form and any bright colour.
  • Correction Strategy: Move to the brightest position available or add a grow light. Stretched growth will not re-compact, so behead the plant and re-root the tidy tips for a fresh, dense start.
• Shy flowering:
  • Cause & Symptoms: Grown too soft, too shaded or too warm in winter, it produces lush leaves but few of its showy yellow flower clusters.
  • Correction Strategy: Give full sun, lean gritty soil and a cool, dry, bright winter rest, which triggers the heavy spring flowering.
• Sunburn / scorch:
  • Cause & Symptoms: A plant moved abruptly from shade or indoors into strong summer sun develops bleached white or brown scabby patches on the most exposed leaves.
  • Correction Strategy: Harden it off over one to two weeks, increasing sun gradually. Scarred leaves will not heal but new growth adapts; provide light afternoon shade in the hottest, driest climates.

What Helps – Products & Tools

For this stonecrop keep the toolkit simple and gentle: isopropyl alcohol on a cotton bud for spot-treating mealybugs, insecticidal soap and neem oil for aphids, scale and mites, and-outdoors-iron-phosphate slug pellets, copper barrier tape or sharp grit against slugs and snails. Beneficial nematodes deal with vine weevil grubs in pots, sulphur or potassium-bicarbonate spray checks rust and mildew, and a bag of horticultural grit or pumice is the best long-term insurance against the rot that causes most losses.