Carmona (Fukien tea)

Carmona microphylla, the Fukien tea, is a small evergreen shrub from southern China and south-east Asia, named for the province of Fujian. It has tiny, dark, glossy leaves with a rough upper surface and a pale underside, pale grey-brown bark that cracks with age, and small white flowers through much of the year, followed by red berries that turn black. It is one of the classic trees of Chinese penjing and has been grown in pots there for centuries. Elsewhere it is sold as an indoor bonsai, often as a young, heavily pruned S-curve trunk, and it is the one of the common indoor trees most likely to be lost in its first winter.

It suits a home only on its own terms. It wants more warmth, more light and more humidity than a ficus, and it resents change. Given a bright window, a steady temperature and a careful hand with the watering can, it is a tree of real character, with flowers that a ficus or an elm will never give, and leaves so small that even a tree of fifteen centimetres reads as a tree. Given a dark corner, a draught and a wet pot, it drops its leaves within a fortnight and does not always recover. The difficulty rating is honest: this is the tree for the second or third year of the hobby, or for the beginner who has a very bright room and is prepared to pay attention.

The mistake that loses most Carmonas is overwatering, usually in winter. The fine roots rot in a pot that stays wet, and the first sign is leaves yellowing and dropping from the inside of the crown while the surface of the mix still looks damp. The tree should be watered thoroughly when the surface has dried, then left until it dries again; in a cool room in December that may be only once in ten days. A tree bought in dense, peaty compost is best moved into a free-draining mix at the first warm opportunity, because the compost holds water for days and the roots suffocate. The second mistake is a dark windowsill. Carmona needs the brightest window in the house, south or west facing, with the pot close to the glass, and in winter it benefits more than any other indoor tree from a grow light on a timer. The third is dry heat: a sill above a radiator cooks the pot and drops the humidity below what the leaves tolerate.

Through the year the tree lives on its bright sill from September to June. It can go outside for high summer, July and August in most of the country, in a sheltered, partly shaded spot once nights are reliably above about 12 to 15 degrees, and it must come back in before the first cool night, earlier than a ficus would. Many growers keep it inside all year rather than risk the moves, and that is reasonable in a bright room. Humidity is the thing to manage: a tray of wet gravel under the pot, a group of plants together, or a bright bathroom all help; misting helps for an hour and is not a substitute.

Carmona grows slowly and steadily rather than in flushes, and it is not strongly apically dominant, so the crown fills out from pinching rather than from hard pruning. New shoots are pinched back to two or three leaves once they have four or five, which builds fine twigging over a season or two. It buds back on old wood, but hard pruning should be done in late spring when the tree is growing, not in winter. The wood is brittle and the bark bruises, so wiring is done on young shoots only, lightly, and checked often; older branches are better guyed than bent. Cuts seal slowly, and a wound paste on anything larger than a pencil is worth using.

The interest is in the flowers, small, white and five-petalled, which appear in little clusters on new growth more or less whenever the tree is growing well, so a happy tree in a bright room flowers on and off from spring to autumn and sometimes in winter. Red berries follow if the flowers are pollinated, and they ripen to black; they are best removed on a young tree so the energy goes into growth. The leaves are the other pleasure, tiny and glossy, with a rough surface that catches the light; the pale, cracking bark comes with age.

Repotting is a late spring job, when the days are long and the house is warm, every two years for a young tree and three or four for an older one, and the roots are cut back by no more than a quarter, because the tree recovers slowly from root work. Feeding is fortnightly from spring to early autumn with a balanced liquid feed at half strength, and stops in winter. A Carmona that is doing well should simply be left to do well; most of the harm done to this species comes from doing too much. Every figure here is a rule of thumb, and your room will set the real one.

• Informal upright (moyogi): a gently moving trunk with a layered crown of small leaves is the natural habit of a tree pruned over years
• Broom (hokidachi): fine, dense twigging comes readily from pinching, and the tiny leaves make a convincing rounded crown at small size
• Slanting (shakan): the trunk leans towards the light on a windowsill, and a deliberate lean with a counterbalancing crown turns that into a design
• Cascade (kengai): young shoots are flexible enough to wire down, though the tree is slow and the style needs patience
• Root over rock (sekijoju): the surface roots thicken and spread, and a stone shows them off, though growth is slower than on a ficus

2 parts akadama, 1 part pumice, 1 part lava (by volume), with a little composted bark if the room is very dry

Carmona is lost to wet, airless soil more than to anything else; the mix must drain fast and let the roots breathe, while the bark holds just enough water between drinks in a dry house.

A flowering tree takes a glazed pot, by the rule of thumb, and Carmona's white flowers and dark leaves look best over a cream, pale grey or soft blue glaze; a deep green is handsome too. The length is about two thirds of the tree's height, the depth about the width of the trunk at the base, but a little deeper than the rule is forgiving for an indoor tree, because the mix dries more evenly and the roots stay cooler.

Ovals and soft-cornered rectangles suit the informal crowns; a round or drum pot suits a small broom. The pot must have generous drainage holes, more than most indoor pots are sold with, and it should never stand in a saucer of water.

Scale insects are the commonest problem indoors, small brown bumps along the stems and under the leaves that are wiped off with a cotton bud and a drop of washing-up liquid in water, then checked for weekly. Mealybug shows as white fluff in the leaf axils and is treated the same way. Red spider mite comes with dry, warm air, stipples the leaves pale and spins fine webbing; raising the humidity and rinsing the foliage sets it back, and a soap or horticultural oil spray finishes it. Whitefly can appear on a tree that has been outside.

Leaf drop is nearly always cultural rather than a pest: a change of place, a cold draught, dry heat or a wet pot. The tree tells you by yellowing from the inside of the crown. Fix the cause and wait; a Carmona with green buds will refoliate, slowly. A yellow leaf with green veins is a sign of chlorosis from hard tap water, and a dose of chelated iron and a switch to rainwater help.

What every month's line rests on: RHS H1c (https://www.rhs.org.uk/plants/207663/carmona/details, checked 30 Oct 2026): can be grown outside in summer, minimum 5 to 10 °C. In practice a Carmona in a bonsai pot sulks and drops leaves below about 12 °C, so we treat it as warmer than its rating: a warm, bright, humid spot all year and outside only in high summer.