Conifer Care: Watering, Feeding and Reading Brown Foliage

Watering: deep, infrequent, and mostly in the first three years

A newly planted conifer has all its roots inside the volume of the old pot, and that volume dries out far faster than the surrounding ground. For the first two to three growing seasons, water thoroughly once a week during dry spells rather than lightly every day. Five to ten gallons (20-40 liters) delivered slowly at the base soaks the full root depth; a brief sprinkle wets the mulch and evaporates.

The way to check is to push a finger or a screwdriver into the soil at the edge of the original root ball, four to six inches (10-15 cm) down. If it comes out with damp soil clinging to it, wait. If it comes out dry and clean, water. Do this rather than watering on a schedule, because a week of cool cloudy weather uses a fraction of the water a week of hot wind does.

Established plants, three years in and rooted out into the surrounding soil, rarely need watering at all except in extended drought. When they do, the same rule holds: one long soak beats five short ones. The exception is any conifer growing in a container, in a raised bed, or against a wall where the roof overhang keeps rain off. Those never become self-sufficient and need checking through every dry period for their whole life.

Overwatering kills more conifers than underwatering. Roots sitting in airless wet soil die, the plant then cannot take up water, and the foliage browns exactly as it would in drought. If foliage is browning while the soil is damp, stop watering and improve drainage. Adding more water to a drowning plant is the most common way gardeners finish one off.

Feeding, or mostly not feeding

Conifers are adapted to poor soils and grow steadily without feeding in any reasonable garden ground. Heavy nitrogen produces soft, fast, pale growth that is more attractive to aphids and mites, more likely to be damaged by cold, and more likely to open the plant out and spoil its shape. If a conifer is growing well and holding good color, feed it nothing.

There are three cases where feeding helps. A plant in a container has no soil reserve and benefits from a slow-release balanced feed applied once in spring. A plant in genuinely thin sandy or chalky ground with visibly short annual growth benefits from a light spring feed. And a plant showing overall yellowing with no drainage problem may be short of magnesium or iron, which shows first on the older foliage and responds to a specific corrective rather than to general fertilizer.

Mulch does more than fertilizer for a conifer. Two to three inches (5-8 cm) of bark, wood chip or leaf mold over the root area keeps soil temperature even, conserves moisture, and feeds the soil slowly as it breaks down. Top it up each year, keep it clear of the trunk, and spread it out to the drip line rather than piling it in a ring near the stem.

Which brown is normal and which is not

Every conifer sheds its oldest foliage, and on most forms it goes brown before it drops. Interior needles or scales turning fawn and falling from the inner part of the branch, evenly around the plant, mostly in autumn, is the plant clearing shaded foliage it no longer supports. It is not a disease and there is nothing to do about it except shake or brush the dead material out of dense forms so it does not sit and hold moisture.

Browning that starts at the tips of the newest growth, or that hits one side of the plant only, or that appears as whole sprays going fawn while neighboring sprays stay green, is not normal. Tip browning on the exposed side after cold weather is wind scorch. A single branch or section browning while everything else is green points to damage or disease in that branch, and cutting into it will usually show discolored wood at the point of failure.

Overall dulling of color with no obvious pattern, over a season or two, almost always means roots. Check drainage, check the planting depth at the collar, and check whether anything has changed nearby: a new patio, a raised bed, a downspout redirected, a lawn edge built up. Conifers respond slowly, so the cause is often a year or more before the symptom.

Keep a note each season of which plants browned, where on the plant it started, and what the weather did beforehand. Wind scorch, drought and root problems all look similar at a glance but they follow different patterns over the years, and only a record makes the pattern visible.

Snow, ice and the shape you are trying to keep

Columnar and multi-stemmed forms splay open under heavy wet snow, and once the branches have been bent past a certain point they never fully return. Where snow is a regular event, tie the plant loosely with a soft wide band spiralled up the outside before winter, tight enough to hold the branches together and loose enough not to mark the bark. Remove it in spring so the plant does not grow into the ties.

If snow has already loaded a plant, brush it off upward with a broom rather than shaking the trunk, which snaps frozen branches. Do not try to remove ice; the branches are brittle and you will do more damage than the ice would. Let it melt and assess afterwards.

Branches that have been bent out but not broken can often be tied back into position for a full growing season and will hold once the wood has thickened. Broken branches should be cut back cleanly to a live side shoot inside the green foliage. On most conifers a cut into bare brown wood never regrows, so the cut position matters more than the tidiness of the wound.