Repotting a Dracaena: When to Do It, Pot Size and Compost

It likes a tight pot

Dracaena is slow rooting and is perfectly happy slightly pot bound. Repotting on a schedule, or into a pot two sizes larger to save doing it again, is one of the most reliable ways to kill an otherwise healthy plant. The unrooted compost around the outside stays wet for weeks, and the roots rot in it.

Most plants need moving every two to three years, and a large specimen can go longer if you replace the top layer of compost instead. Wait for the plant to tell you.

1. Roots out of the drainage holes Thick orange or yellow roots pushing out of the bottom mean the pot is full. Lift the plant out and if the rootball holds its shape as a solid block, it is time.
2. Water runs straight through Water appearing at the bottom within seconds while the compost barely darkens means roots have replaced most of the soil and the water is finding channels.
3. The pot tips over When the top growth outweighs the pot, the roots are equally cramped. That balance is a signal in itself.
4. New growth has stalled If light, warmth and watering are all right and the plant has produced nothing new through a whole growing season, look at the roots.

One size up, and no more

The right increase is about one to two inches (3 to 5 cm) in diameter. That gives the roots somewhere to go without leaving a large volume of wet, unused compost around them.

To hold a plant at its current size, shave an inch (2 to 3 cm) off the outside and bottom of the rootball, return it to the same pot with fresh compost, and cut the top back by a similar proportion in the same season, though not on the same day.

A mix that drains

Dracaena roots want air as much as water, and a dense peat based compost holds far too much for them. Build the mix around drainage and you remove most of the problems people have with this plant.

1. A workable mix Roughly six parts general houseplant compost, two parts perlite or coarse grit and two parts fine orchid bark. It should feel open in the hand and water should run through it freely.
2. Avoid water retaining additives Composts sold with added water retaining gel are the wrong thing here. They are designed to keep summer containers wet, which is the opposite of what a dracaena wants.
3. Do not reuse old compost as it is Old compost has collapsed, drains badly and holds accumulated salts. Replace at least half with fresh, especially if the plant has had brown tips.
4. Skip the crocks A layer of gravel in the bottom does not improve drainage, it raises the wet zone into the rootball. A pot with real drainage holes and an open mix is what matters.

Doing it

Repot in late spring or early summer, while the plant is growing and can replace roots you damage. Avoid it entirely between late autumn and early spring, when cut roots simply rot.

1. Water the day before A slightly damp rootball comes out in one piece. A bone dry one crumbles and takes half the fine roots with it.
2. Tease the outside only Loosen the outer half inch (1 cm) of roots so they grow outward instead of continuing to circle. Do not comb the whole rootball out; dracaena resents heavy root disturbance.
3. Cut away anything black Firm roots are pale orange or cream. Anything black, soft or smelling sour is dead and should be cut back to firm tissue with clean pruners.
4. Plant at the same depth Set the cane at exactly the depth it was before. Burying the base deeper invites stem rot, which on a dracaena is not recoverable at that point.
5. Water in once, then wait Water thoroughly to settle the compost, let it drain, and then leave it considerably longer than usual before the next watering. The fresh compost is holding water the roots cannot yet reach.

Do not feed for six to eight weeks after repotting. Fresh compost carries enough, and fertilizer on cut roots does damage rather than good.

Topdressing instead of repotting

For a large plant in a pot you cannot realistically lift, replacing the top two inches (5 cm) of compost each spring does most of the work of a repot. Scrape off the old surface, including any white salt crust, taking care not to tear roots, and replace it with fresh mix.

Combine that with a thorough flush at the same time and a big dracaena will run happily for five years or more in the same container.

Splitting a multi cane pot

Plants are usually sold with two or three canes of different heights in one pot, and these are separate plants rather than one branched specimen. They can be separated when you repot, provided each cane comes away with its own roots.

Work the rootball apart with your fingers rather than cutting where you can, and pot each cane individually one size down from the original. Do it in late spring so all the pieces have the full growing season to re-establish, and keep them out of strong light for the first fortnight.

Record the date you repotted and the pot size you moved into. Two years on, that note tells you whether it is due again far more reliably than guessing from the size of the plant.