Repotting Guide · Late Spring
May is the season's last clear window for hardy trees and a wide-open one for everything tender. Deciduous repotting is closing as leaves harden, conifers still have a little runway, and tropicals, cacti, and succulents are all growing fast. It is also azalea time.
What to repot in MayAcross all four families we grow for — timing depends on watching your plant, not just the date.
Outdoor & Temperate Bonsai
The deciduous window is closing — only repot late-leafing trees still showing soft growth. Junipers and pines remain workable while new growth is soft. Repot satsuki azaleas (Rhododendron indicum) now, just after they finish flowering, into an acidic, moisture-retentive substrate such as kanuma rather than the standard gritty mix.
Tropicals & Tropical Bonsai
Once nights stay reliably above about 50°F (10°C) you can move tropicals outdoors and repot freely. Ficus, Fukien tea, sageretia (Sageretia theezans), and dwarf jade all respond beautifully to the warmth.
Cacti
Excellent conditions. Repot and pot up actively growing plants; many desert cacti are setting buds or beginning to bloom now, so finish root work before flowers open.
Succulents
A great month — including the famous Lithops (Lithops, living stones), whose growing season is starting. Repot them now and keep them dry for a week afterward. Sempervivum (hens and chicks) can be divided and replanted.
Timing by USDA zone
Spring runs later as you go colder and earlier as you go warmer — shift the calendar to match your climate.
Catching up — main tropical, cactus, and succulent repotting begins as frost danger passes.
Finish conifers and azaleas; move tropicals outside.
Hot already — repot in the cooler morning and shade fresh work.
🌱 Tip of the month
Azaleas are the exception to one-mix-fits-all. They want acidic, water-retentive kanuma, not the sharp inorganic blend that suits junipers and pines.
✨ Fun fact
Lithops disguise themselves as pebbles to avoid being eaten — their Afrikaans nicknames translate to sheep hoof and cattle hoof for their stony, split look.
Soil for this month
Everything above drains fast and breathes — exactly what these plants want at repotting time.
A note on timing: plants don't read calendars. Use these months as a guide, but let the plant make the final call — repot deciduous trees as buds crack, conifers as new growth softens, and tender plants only while they're in active growth. Always step up just one pot size and match the mix to the plant.