Valerian

Peculiar to valerian and its relatives, and the single most common reason a new valerian planting simply disappears. Plan for it at planting rather than afterwards: mesh over the crown, soil firmed, and no spare root left lying about after you divide. Rats are drawn to valerian root for the same reason, which is the old basis of the Pied Piper story and of using the root to bait traps.

Soil freshly scratched out around the crown, with the plant lolling sideways or lifted clear of the ground. Fur caught on stems or on the mulch. Root pieces dragged several feet away and left chewed. A newly planted division that has been pulled up overnight and abandoned on the path. Rolling, flattened patches in the mulch beside the plant. Damage that arrives in bursts - nothing for weeks, then a wrecked planting the night after you divide or dig. Established clumps left alone while a new planting a few feet away is destroyed, because the interest is in disturbed roots and their scent.

Re-cover and re-firm the planting the moment you find damage, because a cat that has found the roots will come back. A plant pulled up but still holding roots usually recovers if you replant it promptly, firm it in, water it, and cage it; trim off any badly chewed root and cut the top growth back by a third to reduce the load while it re-roots. Root pieces that have been dragged off and gnawed are lost. Scent deterrents work for a while and then stop, so treat them as a supplement to physical cover rather than a substitute for it.

Cover new plantings. A square of wire mesh or hardware cloth pegged flat over the crown, left until the plant has rooted in and filled out, is cheap and is the only thing that reliably works. Firm the soil well after planting or dividing so there is no loose earth to dig, and water it in to settle the scent down. Never leave lifted roots, trimmings, or spare offsets lying on the soil - bag them or bin them straight away, because they are what draws a cat in. Do the dividing and washing somewhere the cat cannot reach, and expect the heaviest pressure in the day or two after any digging. Established clumps generally look after themselves.

Valerian root contains actinidine, a compound that triggers the same euphoric response in domestic cats that catnip's nepetalactone does - and it reaches some cats that catnip does not, so a cat indifferent to catnip may still be a menace here. Behavioral studies put the response rate at roughly half of cats. The reaction is to the root rather than the leaves, so trouble comes whenever roots are exposed or disturbed: at planting, after division, around a freshly dug crown, and wherever a rooted offset has been left lying. Cats roll on the spot, dig at the crown, chew and drag away root pieces, and will return to a patch they have found. It is a nuisance rather than a disease, and it matters most in the first season, when a small plant cannot afford to have its roots hauled out of the ground.

Chiefly a seedling problem, and a predictable one - the damp, rich, mulched soil valerian wants is ideal slug habitat, and the soft young leaves of a first-year rosette are easily stripped. Established four-foot clumps shrug them off entirely. Concentrate protection on new sowings and freshly set-out transplants in spring, and keep the mulch pulled back from young crowns.

Irregular ragged holes chewed out of the middle of leaves and along the edges - not the clean-edged cuts a caterpillar leaves. Seedlings that vanish overnight, or that are cut off at soil level with nothing left behind. Silvery dried slime trails across leaves, soil, pots, and paving in the morning: this is the giveaway that tells you it was mollusks rather than an insect. Chewed pits in ripe fruit, especially where it rests on the ground. Damage that shows up on the lowest, dampest leaves first and gets worse after rain or evening watering. Turn over a board, an upturned pot, or a clump of dense mulch during the day and look for the animals themselves sheltering in the cool underneath.

Hand-picking works and costs nothing: go out an hour after dark with a headlamp, drop what you find into soapy water, and repeat nightly for a week or two - persistence is what wins, not any single product. Shallow beer traps sunk to soil level catch them too, but need emptying and refilling daily to be worth anything. Iron-phosphate bait is the standard control and is far lower-risk around pets and wildlife than the old metaldehyde products, but it is not harmless: many formulations include EDTA, and a dog that eats a quantity of pellets can develop iron toxicosis. Scatter it thinly per the label, never in piles, and keep dogs off a baited bed. Clear fallen foliage and debris in autumn, where the eggs are laid. In a wet climate this is a population you manage each season rather than one you eradicate - and on most established plants light grazing is cosmetic and needs nothing at all.

Take away the daytime shelter first: lift boards and upturned pots, clear piles of debris, keep dense mulch pulled back from crowns and stems, and give crowded plantings enough airflow to dry out. Water in the morning rather than the evening so the surface is dry by the time they come out. Copper tape around containers and raised beds gives them a shock they will not cross, and it is the one barrier that reliably works. Get plants past the vulnerable stage quickly - start seedlings in pots and set them out at a decent size rather than direct-sowing into a cold wet bed, since most plants stop being worth defending once the leaves toughen. Leave the ground beetles, frogs, toads, and ground-feeding birds alone, because they eat mollusks all night for free and broad-spectrum slug pellets kill them too. Where thick-leaved or resistant varieties exist for what you are growing, they take far less damage.

Slugs and snails are nocturnal mollusks that rasp ragged holes in soft leaves, shear off seedlings at ground level, and chew into ripe fruit that touches the soil. They feed at night and in the early morning and spend the day hidden under boards, pots, dense mulch, leaf litter, and low foliage, becoming active in exactly the cool, damp, shaded conditions that suit young plants. Damage is heaviest in wet spells and on tender spring growth: a single wet week can erase a row of seedlings while an established, tough-leaved plant of the same species is barely marked. They lay clusters of small pearly eggs in damp soil and under debris, so a garden with plenty of cover carries a resident population year after year rather than being invaded from outside.

One of several leaf spots recorded on commercial valerian, alongside ramularia and downy mildew, and the one most likely to cost you root size by stripping foliage in a wet summer. Worse in hot humid regions and in second-year stands. Water at the base, space plants for airflow, and clear the fallen foliage in autumn rather than leaving it over the crown.

Numerous small brown-to-tan spots, sometimes with darker margins, spreading on the foliage after wet spells.

Remove and trash affected leaves promptly; improve airflow; copper can protect new growth if pressure is high.

Space for airflow, water at the base, use disease-free seed, and rotate away from Apiaceae beds.

Fungal disease (Septoria petroselini) that spots parsley foliage with small tan-centered lesions in wet, humid weather, disfiguring the leaves.

The main disease limit on the crop. Valerian wants constant moisture but not standing water, and second-year stands in heavy or poorly drained ground lose roots to soil fungi - Montana State's production trials found a Phoma root rot cutting yields badly in year two while first-season roots came out clean. On ground that has rotted a crop, harvest on a one-year cycle instead and plant into a raised, well-structured bed.

Wilting in the middle of the day on a plant whose soil is damp - the classic tell, and the reason people water a rotting plant and finish it off. Leaves yellowing from the bottom up, dull off-color foliage, and growth that stalls for no visible reason. Whole shoots, or one side of the plant, collapsing while the rest still looks fine. Soft, dark, or mushy tissue at the base of the stem or at the crown, sometimes with a sour smell. Lift a failing plant and look at the roots: healthy ones are firm and pale, rotted ones are brown or black and slimy, and the outer layer slips off between your fingers leaving a thread of core behind. Seedlings that topple over at soil level are the same problem, called damping-off.

There is no cure for tissue that has already rotted, so act on the conditions rather than looking for a spray. Stop watering at once and fix the drainage - open up compacted soil, or move the plant to a raised, sharply drained position or a container. Lift a badly affected plant, cut away every soft dark root and rotted section with a clean blade back to firm pale tissue, and replant only the healthy parts into fresh free-draining soil or mix. Often the better move is to give up on the plant and save its offspring instead: cuttings, offsets, or divisions taken from firm healthy growth root readily and give you a clean start. Bin the rotted material rather than composting it, and correct the drainage before you replant, because the rot comes straight back in the same wet spot.

Drainage is the whole defense. Match the plant to the site first - something that wants sharp drainage will not survive heavy clay or a low, water-collecting spot however well you tend it. Where the ground is heavy, plant on a raised bed, berm, or slope, or grow in a container. Set plants at the depth they were already growing, since burying the crown or the root flare is a common cause of rot, and keep mulch pulled back a few inches from the stem base instead of piled against it. Water the soil rather than the calendar: check that the top inch or two is dry before watering again, cut back hard in cool weather and winter dormancy, and never leave a pot standing in a full saucer. Do not plant or dig in soggy ground, and go easy on rich amendments for plants that want it lean. Rotate annual crops, and start with clean healthy plants and fresh mix.

Root rot is not one organism but a group of soil fungi and water molds - Pythium, Phytophthora, Fusarium, Rhizoctonia and others - that sit harmlessly in most soils and only turn destructive when the ground stays saturated. Waterlogged soil drives the air out, the roots suffocate, and the weakened tissue is invaded and goes soft, brown, and stringy. Because the damage is underground you usually see it first as something that looks like drought: wilting, yellowing, stunting, a plant that does not respond to being watered. Overwatering, heavy compacted ground, a low spot that collects runoff, a pot with no drainage or a saucer left standing full, and cold wet soil in winter are the usual causes. Once roots have actually rotted there is no cure - this is a problem you prevent rather than treat.