Mature size & growth rate

How big does Forest Spurflower (Plectranthus fruticosus) get?

Also called Forest Spurflower, Spur Flower, Blue Spurflower.

More about forest spurflower

About Forest Spurflower

Plectranthus fruticosus · also called Forest Spurflower, Spur Flower · houseplant

Plectranthus fruticosus is a fast-growing, erect evergreen shrub native to the forest margins and scrub of South Africa's eastern coast, where it can reach 2 m tall. It produces showy terminal spikes of soft blue to mauve flowers in late summer and autumn that are highly attractive to bees, and performs best in partial shade with humus-rich, well-drained soil. The most important care fact is to prune it back by up to one-third in late winter to keep growth compact and promote a flush of new flowering stems. This species is not individually listed on the ASPCA database; treat as mildly-toxic around pets.

Mature size: 1.5-2.5 m tall with a spread of 1.5-2.5 m

Watch for — Leggy, sparse growth: Without annual pruning, the shrub becomes woody and bare at the base. Cut back by one-third in late winter before new growth emerges to maintain a compact, bushy shape and maximise flowering.

Indoor size vs how big it gets in the wild

Forest Spurflower grows on a tree's timeline and scale — indoors it becomes a tall, trunked statement plant rather than a tabletop one. Indoors and in a pot, expect 1.5-2.5 m tall with a spread of 1.5-2.5 m. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Growth rate and years to mature

Forest Spurflower is a fast grower. Realistically, expect two to four years from a young plant to a room-filling specimen in good light. Its feeding profile backs this up: feed monthly with a balanced liquid fertiliser from march to september; deadhead spent racemes to extend the flowering season and apply a potassium-rich feed in late summer to boost flower production.

Want this turned into the right next pot at the right moment? The pot size calculator and the forest spurflower repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast forest spurflower grows.

How to keep forest spurflower smaller

You are not stuck with the maximum size. For forest spurflower specifically, these are the levers, in order of impact:

The decisive tool is the secateurs: forest spurflower can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape.
Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size.
Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height.
Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

The keep-it-smaller method, step by step

Pick the new height. Decide how tall you want forest spurflower and find a leaf node or branch point just below that.
Top the main stem. Cut the main growing tip cleanly just above that node in spring; this permanently caps the height and forces side branches.
Keep the pot snug. Avoid jumping to a much bigger pot — a slightly restricted rootball keeps the whole plant smaller.
Maintain the shape. Prune back the tallest new leaders each spring to hold it at the height you chose.

How to grow forest spurflower bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for forest spurflower the accelerators are:

The biggest lever is light — a tree-type plant in dim light barely gains height; move it brighter.
Pot up a size every year or two while young; restricted roots are the main thing holding height back.
Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.

Light is almost always the ceiling. The forest spurflower light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When forest spurflower outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for forest spurflower:

The top leaves pressing against or bent by the ceiling — the classic "this is now too tall indoors" sign.
It has to be moved away from a light source it has literally outgrown.
Roots filling the largest pot you can reasonably keep indoors — at that point it is top-or-prune or move it outside (if hardy).

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the forest spurflower repotting guide. If you want more of this plant instead of a bigger one, the forest spurflower propagation guide turns prunings into new plants.

Forest Spurflower size — frequently asked questions

How big does forest spurflower get?

Forest Spurflower reaches 1.5-2.5 m tall with a spread of 1.5-2.5 m when grown indoors. It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Is forest spurflower slow or fast growing?

Forest Spurflower is a fast grower. Expect two to four years from a young plant to a room-filling specimen in good light. Forest Spurflower grows on a tree's timeline and scale — indoors it becomes a tall, trunked statement plant rather than a tabletop one.

How long does forest spurflower take to reach full size?

Roughly two to four years from a young plant to a room-filling specimen in good light. Light, pot size and feeding move that timeline more than anything else.

How do I keep forest spurflower smaller?

The decisive tool is the secateurs: forest spurflower can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape. Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size. Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height. Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

How can I make forest spurflower grow bigger or faster?

The biggest lever is light — a tree-type plant in dim light barely gains height; move it brighter. Pot up a size every year or two while young; restricted roots are the main thing holding height back. Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.