Four Problems When Dividing Pups: Few Roots, Twin Crowns, a Blackening Mother, a Burst of Rescue Pups

A staghorn fern (Platycerium) pup does not always develop the way you would hope: no shield and barely any roots, two buds that might or might not be a genuine twin crown, or a mother's growing point turning black after her pups come off. How to read and handle each of these three cases follows below. Timing is covered in When Is a Staghorn Fern Pup Ready to Divide? and technique in How to Divide a Staghorn Fern Pup.

A pup with no shield and few roots: moss-ball it first

Some pups come off before they have grown a shield frond of their own, with only a few roots, so the growing point hangs unsupported behind them and wobbles at the slightest touch. Mounted straight onto a board like that, they often snap off or fall away entirely. The safer route is to wrap them into a moss ball first: pack sphagnum behind and around the growing point, then build up alternating layers of moss and an airy material such as bark or tree-fern fibre, with a little fertiliser worked in, and bind it with several turns of cotton thread that avoid the growing point and any new scales. Trim the moss round, set the pup growing-point-up, and grow it lying flat rather than hanging it. Once the shield has filled in and roots have filled the ball, cut the thread and mount it properly. A tiny pup that has already dropped off on its own, with almost no roots, can simply go into a small propagation box of sphagnum to grow roots on its own.

Twin crowns and mystery buds

Sometimes two buds appear tightly side by side near the growing point — a twin crown. It isn't a disease, but confirm it first: each bud needs its own growing point and its own fronds, not just fronds from one bud crossing over each other, so watch for a round or two of growth before acting. Option one: score the join between them with a clean blade without separating them, let each side grow its own roots for about a month, then divide and mount as usual. Option two: keep the main bud and scrape or pinch off the smaller one, suited to a bud too small or under-rooted to survive on its own. Option three: when both buds are large and full, each with its own growing point and fronds, cut straight down between them and share the roots evenly; pot each half in sphagnum to root, and move it to a board once new fronds push out. Early autumn, once the heat has broken but the air is still humid, is when they recover fastest.

For an unidentified side bud, the rule is simple: leave alone anything above and aligned with the main growing point. Anything to the side or below can be removed outright, or watched in a closed, humid box (indoors, under 32°C) — keep it only once it grows its own growing point. A pup worth dividing needs its own growing point, its own fronds and enough roots. Either way, avoid the height of summer and let the cut dry for a few days before resuming normal watering.

When the mother's bud is half black

If a mother plant's growing point is black on one side and still green on the other, don't write it off yet. As long as green tissue remains and new fronds keep coming, the plant is alive. This shows up most often in species that pup heavily — the more pups crowding a mother, the more strain on her, so new fronds come in smaller and the bud loses its sheen. The order to work in: check the growing point first; then remove the pups and mount them separately, clearing away any blackened, rotten tissue and old medium from the mother at the same time; then move her out of direct sun — an hour or two of full sun in summer is enough to scorch a bud, so keep her in filtered light through the hottest months and add sun back gradually in autumn; and for the two weeks after removing pups, water less and keep the light filtered. Don't discard a struggling mother too quickly, and don't reach for heavy watering or fertiliser at this stage. P. willinckii is a common example of a heavy pupper; if the blackening spreads into the fronds themselves, see frond diagnosis.

A Burst of Rescue Pups: Don't Rush to Split Them

When a growing point is injured, roots get crowded, or conditions turn hostile, a mother plant can throw out a dense cluster of small pups at once — growers call these rescue pups. Splitting them apart the moment they appear does the most damage. Whether one is ready comes down to whether it has grown its own "face": its own shield frond open, roots of its own behind it. Left crowded together a while longer is the safer route. Where the buds already have a little space between them, you can cut down between two of them without lifting either out, then tuck sphagnum into the cut so it slowly wedges them apart, deepening the cut over several sessions. Separate them for good once each has fronds of about 5 to 10 cm and roots of its own. Use curved, close-fitting pliers to lever each pup free from behind the growing point, roots and all, and pack the gap left on the mother with sphagnum.