Mature size & growth rate

How big does Old Man Saltbush (Atriplex nummularia) get?

Also called Old man saltbush, Giant saltbush, Australian saltbush, Bluish saltbush.

More about old man saltbush

About Old Man Saltbush

Atriplex nummularia · also called Old man saltbush, Giant saltbush · edible

Atriplex nummularia is a large, fast-growing, evergreen shrub native to the arid and semi-arid interior of Australia, where it is one of the most ecologically and agriculturally significant native plants. Its silvery, salty leaves are used as a distinctive seasoning in modern Australian cuisine and provide highly nutritious browse for sheep and cattle in dryland farming. The single most important care fact is that this plant must have full sun and free-draining soil — it tolerates extreme salinity, alkalinity, and drought but is sensitive to waterlogging and high humidity. It is not listed as toxic by the ASPCA, but oxalate content means it should be classified as mildly-toxic for pets.

Mature size: 2.5–3.5 m (8–11 ft) tall, spread up to 5 m (16 ft).

Watch for — Lucerne flea and earth mites: The lucerne flea (Sminthurus viridis) and red-legged earth mite (Halotydeus destructor) are the most documented pests, causing malformation of new growth in young plants; most damaging at the seedling stage — monitor and treat with appropriate miticide or insecticidal soap.

Indoor size vs how big it gets in the wild

Old Man Saltbush 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 2.5–3.5 m (8–11 ft) tall, spread up to 5 m (16 ft).. 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

Old Man Saltbush 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: rarely needs feeding; in highly fertile soil, excessive growth can lead to reduced leaf quality and increased pest susceptibility — grow lean for the best compact form.

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

How to keep old man saltbush smaller

You are not stuck with the maximum size. For old man saltbush specifically, these are the levers, in order of impact:

The decisive tool is the secateurs: old man saltbush 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 old man saltbush 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 old man saltbush bigger or faster

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

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators.
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 old man saltbush light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When old man saltbush outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for old man saltbush:

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 old man saltbush repotting guide. If you want more of this plant instead of a bigger one, the old man saltbush propagation guide turns prunings into new plants.

Old Man Saltbush size — frequently asked questions

How big does old man saltbush get?

Old Man Saltbush reaches 2.5–3.5 m (8–11 ft) tall, spread up to 5 m (16 ft). 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 old man saltbush slow or fast growing?

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

How long does old man saltbush 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 old man saltbush smaller?

The decisive tool is the secateurs: old man saltbush 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 old man saltbush grow bigger or faster?

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators. 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.