Peanut butter fruit, Bunchosia argentea, is one of the easiest tropical fruits to own and one of the most misunderstood. It is an evergreen to semi-deciduous shrub or small tree of 1-5 m (3-15 feet), hardy only in zone 10 and above, grown for glossy foliage, white flowers with yellow blossom, and clusters of small oval fruits with a pointed tip that ripen yellow, then orange-red, then a deep bordeaux. It also makes a good hedge if you design it that way from the start.
Does it really taste like peanut butter?
Partly, and it is worth being honest about it before you plant one. The smell is the convincing part – the fruit smells like peanut butter, and even the leaves sometimes carry the scent. The flavour is reminiscent of peanut butter but does not go far beyond that. The texture is dense and sticky rather than juicy, which is where most of the resemblance comes from.
Where it genuinely excels is dried. Dried peanut butter fruit tastes like dried figs – richer, sweeter and much more interesting than the fresh fruit. If you end up with a heavy crop, drying is the best thing you can do with it, alongside eating fresh and juicing.
The seed is edible
Each fruit contains one large seed, and it is edible. You eat the fruit whole, seed and all – there is nothing to spit out and no preparation. That is unusual and worth knowing, because a first-time grower often assumes the seed must be removed and ends up with almost nothing left.
Growing from seed – and why nobody grafts it
Peanut butter fruit is normally not grafted. That is not an oversight; it is because the tree grows so easily from seed that grafting buys you nothing. Compare that with most tropical fruit trees, where seedlings are slow, variable and take many years to fruit – here a seedling is a perfectly good tree.
The other half of the answer is speed. A seedling bears fruit in about 2-4 years, which is fast for a fruit tree, so there is no long wait to justify the extra work of grafting.
- Take a seed from a fully ripe fruit and sow it fresh. Tropical seed like this does not store well.
- Use well-drained, rich soil – the same brief as for the mature tree.
- Keep it warm and evenly moist while germinating.
- Grow the seedling on in bright light and pot up as it fills its container, rather than starting it in an oversized pot.
You can also simply buy a plant, which is the shortcut if you want fruit sooner. Plant out in spring, summer or autumn.
Soil, water and light
Give it rich, well-drained soil. Rich matters because this is a productive evergreen carrying fruit over a long season; well-drained matters because the roots will not tolerate standing water.
On water it is more flexible than most tropical fruits. It will manage on a small amount of water, but it prefers an average amount, and that is the setting to aim for if you want fruit rather than mere survival. Fruit is mostly water and sugar; a tree running dry while it is filling fruit will drop it or ripen it small.
Site it in full sun or half shade. Full sun gives the heaviest crop; half shade is genuinely tolerated, which makes it a good candidate for a courtyard or a spot that only gets part of the day.
Cold tolerance
This is a strictly tropical to warm-subtropical tree: hardiness zone 10 and up, meaning winter lows no colder than roughly 1°C (35°F). It also grows in mediterranean climates within that limit. Anywhere with real frost, it has to be a container plant that overwinters under cover – which, fortunately, it takes to very well.
Pruning: the trade-off nobody warns you about
Pruning is where this plant needs a decision from you. Prune at the beginning of winter, after the fruit is finished, and prune with a clear goal: keep the plant small and dense.
The complication is the tree’s habit of throwing out long, rebellious stems – vigorous shoots that shoot away from the framework. Those stems will carry a lot of fruit. Removing them therefore costs you fruit in the short term, and it is still usually the right call, because a plant that is allowed to run into a sprawl of long whippy branches becomes hard to harvest, hard to net against birds, shades out its own interior and produces its fruit at the far end of branches you cannot reach. A compact, crowded plant puts the crop where you can pick it.
Shaping it as a shrub
If you want a shrub or a hedge rather than a small tree, cut the main trunk while the plant is young. That removes the leader’s dominance and forces branching low down, giving you a multi-stemmed bush. It is a decision to make early – it is much harder to convert an established single-trunk tree into a shrub later. Growing it as a shrub is also the recommended form for container plants.
Growing in a container
Container culture works well here, and our growing notes are unusually specific about the method. It fruits in a 5 gallon (20 litre) pot, though bigger is better.
- Start with a pot about 20% larger than the root ball, and step up to the next size each time the roots fill the current one, until you reach the size you want the plant to stay at. Potting up in stages is more efficient and easier on the plant than dumping a small root ball into a huge pot of wet soil.
- Drainage is critical. Make sure the pot has holes, use a peat-based mix, and consider a layer of lava grit or similar coarse material at the bottom.
- Use a saucer, with discipline. When you water, let the saucer fill – but it must be dry again the same day. Water standing overnight around the roots is how container fruit trees are lost.
- Refresh the soil. Potting mix loses its structure and viability over time. Once the plant is large and no longer being potted on, replace part of the soil periodically instead.
- Grow it as a shrub in a pot – lower, denser and far more stable than a top-heavy standard.
Note that it is not a houseplant. A container tree belongs outdoors in the warm months; bring it in only to escape cold.
Flowering, pollination and harvest
Flowering runs through spring and summer, and pollination is done by bees. The fruit harvest is long – spring, summer and autumn – so rather than one glut you get a steady trickle, which suits a plant whose main drawback is a small quantity of fruit per tree. If you want volume, plant more than one; a single specimen is a treat, not a supply.
Pick on colour. The fruit moves from yellow through orange-red to bordeaux, and it is at its best fully coloured and slightly soft. Beyond that the tree asks almost nothing – the work requirement is genuinely nothing special.
Pests and problems
- Birds. The main competitor for the crop. Bright ripe fruit on a small, easily netted shrub is exactly why keeping the plant compact pays off.
- Aphids. Clustering on soft new growth and flower stems; a jet of water or insecticidal soap deals with them.
- Fungal problems. Encouraged by damp, congested growth and poor drainage. Keeping the plant dense is not the same as letting it become a tangle – remove crossing and dead wood at the winter prune so air can move through.
- Low yield. Not a disease, just the nature of the plant. Full sun, average water, rich soil and more than one plant are the levers you have.
For the full plant profile see our Peanut Butter Fruit growing page.
