Repotting a Hoya: Why a Tight Pot Is What You Want

Leave it in the pot longer than feels right

Most houseplant advice tells you to move up a pot size every year or two. For a hoya that advice is actively harmful. These are epiphytes: in the wild the roots run in a thin layer of leaf litter and moss on a branch, they are never in a deep body of soil, and they have no tolerance for being surrounded by compost that stays wet.

A crowded rootball also has a direct bearing on flowering. A hoya that has just been given plenty of new root room puts its energy into leaves and runners, and the flower spurs wait. Leave it snug and it flowers. Three or four years in the same pot is entirely normal and a plant can go longer than that.

When to do it

Repot in late spring or early summer, once the plant is growing again and the room is reliably warm. Broken roots need warmth to be replaced, and a hoya repotted in the cold half of the year sits in damp compost with cut roots and rots.

Never repot a plant that is in bud or in flower, and do not repot immediately after a flush. Wait until it is growing leaves again.

Pot size and material

One size up is the maximum, and often the right answer is the same pot with fresh mix. An oversized pot leaves a mass of compost that no root reaches, and that compost stays saturated for weeks, which is the classic route to hoya root rot.

Terracotta suits a hoya well because it breathes and dries evenly. In a plastic or glazed pot, make the mix coarser to compensate. Any pot must have drainage holes, and the decorative outer pot must be emptied after watering.

The mix

Ordinary houseplant compost on its own is too dense and holds too much water. Build a mix that drains almost immediately and holds air around the roots.

1. A mix that works Roughly two parts orchid bark, one part perlite and one part houseplant compost, with a handful of coarse grit. When you water, it should run out of the bottom within seconds.
2. Add sphagnum if it dries too fast In a small terracotta pot in a bright window the mix may dry out in two days, which is hard to keep up with. A little chopped sphagnum moss slows it without making it soggy.
3. Do not reuse the old mix Old bark collapses to a fine sludge that holds water. Shake as much of it off the roots as comes away easily and start with fresh.
4. Skip the crocks A layer of gravel in the bottom does not improve drainage. Use a mix that drains and a pot with holes, and empty the saucer.

Doing it without losing the flowering wood

The physical operation is fiddly on a trailing or trained plant, and the danger is knocking off the spurs while you handle the stems.

1. Gather the stems first Loosely coil the runners and tie them with soft string before you touch the pot. Loose trailing stems catch on everything and the spurs snap off.
2. Water the day before A slightly damp rootball slides out in one piece. A bone dry one crumbles and tears the fine roots.
3. Disturb the roots as little as possible Do not tease the rootball apart. Remove only the loose material that falls away, drop it into the new pot and fill around it. Hoyas resent root disturbance more than most houseplants.
4. Cut away anything soft or brown Firm pale roots are healthy. Brown, soft roots that slip out of their skin are rotten and must all come off, back to firm tissue.
5. Water once, then leave it alone Water it in, put it somewhere bright but out of direct sun, and do not water again until the mix has dried. Do not feed for about a month.

Write the date on the pot label each time you repot. Knowing that a plant has been in the same pot for four years is exactly the information you want when it suddenly stops growing.