Why is my River Birch root rot?

Likely causes

Work through these in order.

Each cause below has a quick check you can do in about thirty seconds. Stop as soon as one matches. You’ve found your answer.

1. 01

   Chronic overwatering

   Roots need oxygen as much as water. Soil that stays saturated starves the roots, and opportunistic soil fungi move in to finish them off.

   Quick check

   Is the soil wet more than an inch down, is the pot heavy, and do the lower leaves yellow and drop? Unpot and look. White roots are healthy; brown or black mushy roots are rotted.

   What to do

   Unpot immediately. Trim off all soft, discolored roots with clean scissors until you reach firm white tissue. Repot in fresh, well-draining soil and a pot one size smaller. Do not water heavily until you see new growth.

2. 02

   Poor drainage

   Even perfect watering can't save a plant in a pot with no drainage hole, or in dense soil that holds water like a sponge.

   Quick check

   Does the pot have a drainage hole? Is the soil heavy and muddy instead of crumbly?

   What to do

   Repot into a container with drainage and a well-draining mix (potting soil cut with perlite or coarse sand at 3:1). A plant saucer that never empties is as bad as no hole at all.

3. 03

   Pot too large

   A plant in a too-large pot surrounds its small root ball with a mass of wet soil it can't dry out, and the soil stays saturated long enough for rot to set in.

   Quick check

   Is the pot more than two inches wider than the root ball?

   What to do

   Move the plant into a pot only slightly larger than its current root ball. Plants prefer snug pots; the advice to 'give it room to grow' is wrong for almost every species.