Gadenin日本語Get the appYou are keeping an outdoor tree in a room
Fraxinus griffithii is a full-size evergreen tree. In a frost-free climate it reaches 30 to 50 feet (9 to 15 m) in open ground and does it quickly, throwing several feet of growth in a single warm season. The slim multi-stem plants sold for living rooms are young trees grown fast in high light, then cut back and potted. Nothing about that upbringing prepares them for the light level inside a house.
That mismatch is the single most useful thing to hold in your head. Almost every complaint about this plant indoors - thinning canopy, bare lower stems, leaves the size of a fingernail, a slow drip of yellow leaflets onto the floor - is the tree telling you the light is below what it was built for. It is not a fussy plant. It is a bright plant in a dim place.
Treat any indoor evergreen ash as a light problem first. Only after you have moved it to the brightest glass in the house should you start looking at water, feed or pests.
Light: the brightest window you have, and no less
Put it directly in front of unobstructed south-facing glass in the northern hemisphere, north-facing in the southern. East and west windows work if nothing shades them and the plant sits within a foot (30 cm) of the glass. A spot six feet (1.8 m) back from a window looks bright to your eye and reads as deep shade to the tree; your eye adjusts across three orders of magnitude and the plant does not.
The tree tolerates full sun outdoors, so there is no such thing as too much window light indoors. If the canopy is already thin, add a grow light on a twelve-hour timer over the top of the plant rather than moving it repeatedly. Turn the pot a quarter turn every couple of weeks so the shaded side keeps its leaves instead of going bare.
| Position | What the tree does | Verdict |
|---|---|---|
| Touching bright unshaded glass | Holds dense leaf, makes new shoots each warm season | Ideal |
| Within 3 feet (1 m) of a bright window | Holds leaf, growth slower, some inner shading | Workable |
| Mid-room, bright ceiling lights | Steady leaf drop, long bare stems, small new leaves | Will decline |
| Corner or north-facing room | Rapid thinning down to bare twigs | Move it now |
Watering: read the pot, not the day of the week
Push a finger two inches (5 cm) into the compost. If it comes out with damp grit clinging to it, wait. If it comes out clean and dry, water until it runs freely from the drainage holes, then tip out anything standing in the saucer within ten minutes. In a bright warm room a plant in a 10-inch (25 cm) pot will want that roughly every five to eight days in summer and every two to three weeks in the cool part of the year.
This tree drinks hard when it is growing and barely at all when it is cold and dark, so a fixed weekly routine will drown it every winter. Underwatering shows as crisp brown leaflet tips and leaves that shrivel before falling. Overwatering shows as soft yellow leaves, a sour smell from the compost and blackened root tips when you tip the plant out.
- Check before you pour Finger two inches (5 cm) down, or lift the pot. A pot that still feels heavy has water in it. Weight is the most reliable test once you know what dry feels like for that plant.
- Water the whole rootball Take it to a sink or use enough water that it drains out of the bottom. A splash on the surface wets the top inch and leaves the roots at the base of a tall pot permanently dry.
- Drain it properly Never leave the pot standing in water. If it sits inside a decorative outer pot, lift it out and check that the cachepot is empty every time you water.
Feeding, humidity and temperature
Feed only while the tree is visibly pushing new shoots, which indoors means the warm half of the year. A balanced liquid feed at half the label strength every three to four weeks is plenty. Feeding a plant that is not growing pushes salts into the compost and burns the fine roots, and feeding a light-starved tree just produces pale, floppy, oversized leaves that drop within a month.
It is comfortable anywhere between 55F and 85F (13C and 29C), which covers any normal room. Keep it off the direct blast of a heating or cooling vent - a dry stream of air at the canopy dries leaflet edges faster than any humidity tray can compensate for. Household humidity is fine; this is not a plant that needs misting.
Leaf drop after a move is normal
Bring a new evergreen ash home and it will very likely shed a good part of its leaves over the following two to four weeks. The same happens when you move an established plant to a different room, or move it back indoors after a summer outside. It is dropping the leaves it grew under one light level because they cannot pay their way under the new one.
Do not react by watering more, feeding, or moving it again - a plant shedding leaves is using less water, so the extra water sits in the pot and turns a recoverable sulk into root rot. Put it in the brightest spot, water only when the top two inches (5 cm) are dry, and wait. New, smaller, tougher leaves appear once it has settled, usually within six to ten weeks in the growing season.
Bare stems that are still green under a scratch of the bark are alive and will bud out again. Snap-dry brown stems are dead and should be cut back to live wood.
What to write down for next year
Note the window it stands in and how far from the glass, along with the date of any move. Then note when leaf drop started and when new growth appeared. Two seasons of those pairs tell you exactly how long your plant takes to recover from a move, which turns a worrying month into an expected one.
Also record the gap in days between waterings in the warmest month and in the coldest, and the pot size it was in. That is the fastest way to catch the seasonal swing before it drowns the plant, and it makes potting up an informed decision rather than a guess.