Gadenin日本語Get the appFeeding is the mistake
The single most common reason a goumi grows well and fruits badly is that somebody has been kind to it. Nitrogen from a general fruit feed, a mulch of rotted manure, or drift from a vegetable bed next door does two things at once: it drives long soft shoots that carry no flower buds, and it suppresses the root nodules that were supplying nitrogen for free. A well-fed goumi is a nitrogen-fixing plant that has stopped fixing nitrogen.
So the feeding program is nothing. No spring feed, no fruit fertilizer, no manure mulch, no liquid tomato feed while it is in fruit. In poor ground it will still make eighteen to thirty inches (45 to 75 cm) of growth a year, and that is the growth rate you want.
Potassium is the one exception worth considering, and only on very sandy ground where a plant flowers well but drops small pale berries year after year. A light dressing of sulfate of potash in late winter is enough. If you are not sure the plant needs it, it does not.
| Input | Verdict for goumi | Reason |
|---|---|---|
| Nitrogen fertilizer | Never | Suppresses nodulation; drives leaf at the expense of flower buds |
| Rotted manure mulch | Never | Same effect as a nitrogen feed, delivered slowly |
| Bark or wood-chip mulch | Yes, two inches (5 cm) | Holds moisture, shows suckers, adds almost no nitrogen |
| Sulfate of potash | Only on poor sandy ground | Helps berry size where potassium leaches away |
| Lime | Not needed | Tolerates a wide pH range without adjustment |
| Irrigation | First two years, then only in drought | Established roots go deep and find their own water |
Water: two years of attention, then none
A newly planted goumi has a small root system in ground that is, by design, not very moisture retentive. Through its first two growing seasons water it deeply once a week in dry spells, five gallons (20 L) at a time, poured slowly at the base rather than sprinkled over the leaves. Deep and infrequent trains the roots downward; a daily splash keeps them at the surface where the first hot week will find them.
From the third year on, an established plant in open ground needs nothing except in a genuine drought. The exception is the few weeks between petal fall and ripening, when the berries are swelling. A bush that dries out hard in that window drops fruit or ripens small, chalky berries. If the top three inches (7 cm) of soil are dust while fruit is sizing, water once and thoroughly.
Suckers, and deciding which ones to keep
Goumi throws suckers from the base and from roots a foot or two out from the crown. Left entirely alone it thickens into a dense mound six to eight feet (1.8 to 2.4 m) across, which is fine in a hedge and a nuisance around a picked fruit bush, because you cannot get at the middle of it.
Walk the plant once in late spring and once in late summer, and pull or cut out suckers coming up outside the mulch ring. Pulling while they are soft and pencil-thin is better than cutting, because a cut sucker regrows from the base and a pulled one usually does not. Keep one or two strong young stems near the crown each year as replacements for old wood you will remove later.
Suckers with roots attached are the easiest way to make more plants, and since a second plant improves the crop so much, the first few you lift are worth potting rather than composting.
Growing it in a container
Goumi takes to a large pot better than most fruit shrubs, partly because restricting it suits a plant that fruits best under a little stress. Use a container of at least fifteen gallons (55 L) and a gritty, free-draining mix with no added fertilizer. A pot dries out far faster than open ground, so the no-water rule from year three does not apply: check the top two inches (5 cm) twice a week in summer.
Repot or root-prune every third winter, taking an inch (2 to 3 cm) off the outside of the root ball and returning it to the same pot with fresh mix. A container plant that has filled its pot completely flowers heavily and then drops most of the fruit, which is the plant telling you it cannot support the crop on the water available.
Do not use a peat-free all-purpose potting mix with a season's feed already in it for a goumi. Those mixes carry exactly the nitrogen charge you are trying to avoid, and a potted plant cannot escape it.
What to keep in the record
Three things are worth logging each season and all three pay off within a year or two. First, the date the flowers open, because it moves by two or three weeks with the spring and it is the anchor for everything that follows. Second, whether you watered during fruit sizing and how the berry size compared with last year. Third, where and when suckers came up.
The sucker map matters most. Written down over two seasons it shows you which direction the roots are running, which tells you where the next crop of suckers will appear and whether they are heading somewhere you do not want them.