Monkshood

Every part contains aconitine and related alkaloids that act directly on nerve and heart cells, concentrated most heavily in the tuberous root and the seed. There is no antidote, onset can be within minutes, and the quantity required is small. Drying and cooking do not make any part safe.

Watch for: Any ingestion of leaf, flower, seed or root by a person or animal. Early signs are tingling and numbness of the lips, mouth and face spreading to the limbs, then nausea, vomiting, weakness and irregular heartbeat - all of which mean the emergency is already under way.

Prevent: Never eat or taste any part and never prepare it in any form. Wear gloves for every job, keep tubers and cut stems out of the kitchen, label the planting, and site it well away from vegetable beds, herb beds and anywhere root crops are dug.

Treat: Suspected ingestion is an EMERGENCY - call poison control or emergency services immediately and do not wait for symptoms. There is no antidote; treatment is urgent supportive hospital care for heart-rhythm effects. Name the plant and take a piece of it if you can.

The specific accident that puts monkshood in this catalog. Its dormant tuber has been dug, grated and eaten as horseradish, which is fatal - the root is the most poisonous part of the plant, and the two are dug in the same seasons by the same gardener. The confusion is entirely preventable, because the discriminators are unmistakable once known.

Watch for: Any root dug from a bed where monkshood grows or has grown, and any root identified without its leaves attached. A monkshood tuber is short (2-4 in), tapering and blackish-brown, usually with last year's shrivelled tuber attached beside this year's; horseradish root is long, cylindrical, buff outside and cream-white inside.

Prevent: Never plant monkshood in or beside a bed where roots are dug, label both plants permanently, and identify any root you intend to eat by the leaves attached to it - horseradish leaves are large, coarse, crinkled and undivided, monkshood leaves are deeply cut into five to seven palmate lobes.

Treat: The field test is smell: cut or scrape the root, and cut horseradish is violently sinus-clearing within seconds while monkshood root has no smell at all. No smell means discard it and wash your hands. If any has been eaten, call poison control immediately and do not wait for symptoms.

Crown rot is the rotting of a plant at the crown - the growing point where the stems meet the roots, right at or just below soil level. Soil fungi and water molds that live in most ground attack that tissue whenever it sits wet, cold, and airless, and because the crown is the one part a perennial cannot regrow from, losing it usually means losing the plant. It is above all a winter problem: a plant that survives hard frost perfectly well in dry ground rots out in a wet one, and the classic story is a perennial that simply never comes back in spring. Dry-adapted plants growing in heavy or over-improved soil are the most vulnerable, along with anything that has mulch, wet leaves, or piled debris sitting against the crown, and anything planted too deep.

Watch for: A plant that fails to green up or emerge in spring when everything around it does - the most common way this gets discovered, and by then it is already too late. Stems that wilt, blacken, and collapse in wet weather while the soil is clearly damp rather than dry. A crown that is soft, dark, brown, or mushy when you press or lift it, sometimes with a foul smell, instead of firm and pale. New growth that pulls away from the crown with almost no resistance. Clumps browning and going hollow in the middle while the outer growth stays alive. In stands and cover crops, patches wilting, yellowing, and thinning out after wet spells or over a mild wet winter.

Prevent: Drainage and airflow at the crown are everything. Match the plant to the site first: a dry-adapted perennial planted in heavy or enriched ground is on borrowed time whatever else you do. In wet or clay soil, plant on a slope, berm, raised bed, or gritty rock-garden site so water drains away from the crown rather than standing over it. Set plants at the right depth - never bury the crown - and keep mulch, dead leaves, and debris pulled back from it rather than piled against it, since damp material resting on the crown is a common trigger. Do not overwater, and ease right off during dormancy, when a resting plant wants to be barely damp rather than wet. Give crowded plantings enough space and airflow to dry out, and do not sow a stand too thickly. In cold, wet climates, divide in spring rather than fall, so plants are not recovering from surgery through the wettest months.

Treat: There is usually no cure once the crown itself has rotted: the plant is lost, and the job is to save what you can and fix the site. Lift it, cut away every soft, dark, rotted part with a clean blade back to firm tissue, and replant only healthy divisions or firm outer growth into fresh, sharply drained soil or medium. On potted and specialist plants, repotting into fresh airy medium and keeping them drier with better airflow gives the best chance, though a badly rotted crown is usually beyond saving. Bin the rotted material rather than composting it. Replant somewhere better drained rather than back into the same wet spot - or start again from seed, cuttings, or self-sown seedlings, which is the realistic option for anything that resents being moved at all.

The usual reason a monkshood tuber never reappears after a wet winter. Plant in soil that holds moisture but drains freely, avoid winter-wet hollows, keep mulch clear of the crown, and do not set the tubers deeper than they need. Every part of monkshood is dangerously toxic, so wear gloves when lifting and cutting away rotted tubers, and bin rather than compost them.

Aconitine is absorbed through the skin and through any break in it, so this is one of the few garden plants where handling itself carries a warning rather than just eating it. Gardeners handling cut stems, sap and especially dormant tubers with bare hands report tingling and numbness in the fingers.

Watch for: Tingling, numbness or burning in the fingers or lips after weeding, cutting back or dividing; any handling of the plant with cuts or grazes on the hands, or hand-to-mouth and hand-to-eye contact afterwards.

Prevent: Wear waterproof gloves for every task - planting, weeding, staking, cutting, deadheading and dividing - work with no broken skin on your hands, keep sap away from your face, and wash thoroughly afterwards even though you wore gloves.

Treat: Wash the skin thoroughly with soap and water at once. Call poison control for advice if numbness spreads or persists, or if any symptom appears beyond the contact area.

Aphids are small soft-bodied sap-suckers - green, black, gray, pink, or waxy white, and mostly wingless - that gather in dense colonies on the tenderest new growth: shoot tips, buds, and the undersides of young leaves. They breed extremely fast in mild weather, so a few can become hundreds inside a week. Their feeding curls and distorts soft growth, and the sticky honeydew they excrete coats everything below and turns black with sooty mold. Ants often farm and defend the colonies for that honeydew. A few aphids are normal on almost any plant and a healthy plant shrugs them off; only dense, persistent colonies do real damage, and some aphids also spread plant viruses as they feed.

Watch for: Dense clusters of tiny insects packed onto shoot tips, flower buds, and the undersides of young leaves. Curled, cupped, or distorted new growth that never opens properly. A sticky shine on the leaves - and on whatever sits under the plant - that later goes black with sooty mold. Tiny white cast skins left behind where a colony has been feeding. Ants running steadily up and down the stems, which is often the first thing you notice. Mottled, streaked, or misshapen leaves that do not grow out can mean a virus the aphids brought with them rather than the feeding itself.

Prevent: Go easy on nitrogen: the soft, lush growth that heavy feeding produces is exactly what aphids breed on. Check new growth once a week through spring and early summer so you catch colonies while they are still small, and rub the first few out with your fingers. Leave flowering plants nearby and skip broad-spectrum sprays - ladybugs, lacewings, hoverflies, and parasitic wasps do most of this work for free, and they only stay if there is something for them to eat. Keep ants off the plant where you can, since they protect aphids from those predators. Water steadily so plants are not stressed, and check any new plant over before you bring it home or move it indoors, since aphids usually arrive on something else.

Treat: Knock the colonies off with a hard jet of water and repeat every few days - on most plants that alone ends it. Pinch out or prune off the worst-infested tips rather than treating the whole plant. If colonies keep rebuilding, spray insecticidal soap or horticultural oil directly onto the insects, covering leaf undersides, and repeat weekly until they are gone; treat early or late in the day, and never spray a wilted or heat-stressed plant. Avoid broad-spectrum insecticides - they kill the ladybugs, lacewings, and parasitic wasps that were about to solve the problem for you, and aphid numbers usually come back worse afterward. Anything you spray must be labeled for the plant you are treating; follow that label and observe its pre-harvest interval. On anything you eat, wash leaves, heads, and buds well before use, since aphids hide down in crowns, folds, and tight growth.

Wear gloves for every job on monkshood, including dislodging aphids - every part of the plant is dangerously toxic and its poison can be absorbed through the skin.

Powdery mildew is a fungal disease that coats leaves - and often stems, buds, and fruit - in a white-to-gray powder that looks like spilled talcum. It is not one fungus but a large family of them, each fairly specialised to its own group of plants, which is why mildew on one crop rarely jumps to an unrelated one beside it. Unlike most leaf diseases it does not need wet leaves: it thrives on warm dry days followed by humid nights, and it takes hold fastest where plants stand crowded in still air or in shade. The coating blocks light, so heavily covered leaves yellow, brown, and drop early. On many plants that is mostly disfiguring and arrives late enough not to matter; where it strips away the leaves a crop still needed to finish, it costs you size, sweetness, and quality.

Watch for: Round white powdery spots on the upper leaf surfaces that spread and merge until whole leaves look dusted. It usually starts on the oldest, lowest, most shaded leaves and works upward, so check there first. Look at the undersides too, and at stems, buds, and flower stalks, which get coated as it advances. Leaves that yellow, brown, curl, or go crisp and drop early under the coating. New growth that opens small, crumpled, or twisted where the fungus has reached the shoot tips. On plants where it gets onto the fruit, a dull gray film, russeted or scarred skin, and cracking. Late in the season, tiny dark specks scattered through the white felt - that is the fungus setting up to overwinter on the debris.

Prevent: Give plants room. Crowding and still air are the biggest single driver, so space at the full recommended distance, thin seedlings properly, and divide or prune out congested growth until air moves through the plant. Full sun and an open position help; deep shade and a still corner against a wall are where it always starts. Water at the base rather than overhead, and water early in the day so nothing stays damp overnight. Keep plants evenly watered - drought stress at the roots leaves them far more susceptible, even though the fungus itself likes dry air. Go easy on nitrogen, since soft lush growth is the most vulnerable. Where resistant varieties exist for what you are growing, choosing one is the single most effective thing you can do on a plant that mildews every year. Clear infected leaves and stems away at the end of the season rather than composting them.

Treat: Start early: sprays protect healthy tissue, they do not clean up leaves that are already coated. Pick off and bin the worst leaves as soon as you see them, and open the plant up by thinning or pruning so air moves through. On anything that regrows quickly, shearing the whole plant back forces a clean flush and beats spraying. If it keeps spreading, potassium bicarbonate, horticultural oil, or neem applied weekly will hold it - cover both leaf surfaces. Sulfur also works, but it burns the foliage of some plants, should never go on in heat, and must not be mixed with or applied close behind an oil spray. Whatever you use must be labeled for the plant you are treating: follow that label and observe its pre-harvest interval on anything you eat. Do not compost badly infected material. Late-season mildew on a plant that is finishing anyway is usually cosmetic; on a crop still filling out it is worth acting on.

Every part of monkshood is dangerously toxic, so handle mildewed foliage accordingly: wear gloves, bag the material rather than composting or shredding it, and wash up afterwards. Drought at the roots makes mildew much worse on monkshood, so steady watering plus thinning crowded clumps is the real control.