Why Is My Plant Not Growing? The Australian Gardener’s Guide

It’s alive.

It’s not dying.

It’s just… doing absolutely nothing.

You planted it three months ago. You’ve watered it. You’ve checked it. You may have fertilised it. You’ve probably stood over it at least once wondering whether it has any intention of participating in this garden whatsoever.

Still the same size.

So what’s wrong?

Possibly nothing.

One of the hardest things about gardening is that we judge almost everything by what we can see above the soil. New leaves? Excellent. New shoots? Excellent. Plant doubled in size? We are obviously brilliant gardeners.

But plants don’t work from the top down.

They need roots capable of supporting all that growth first, and a newly planted plant can be doing an enormous amount of work below ground while appearing to do very little above it.

Other times, though, a plant really is stuck.

And this is where gardeners often reach for fertiliser.

Plant not growing = plant must need food.

Except that's a bit like deciding every tired person needs a sandwich.

Maybe.

Or maybe they need sleep.

Your plant could be too wet, too dry, too hot, too cold, planted too deeply, sitting in compacted soil, competing with a tree, getting the wrong amount of sun or simply waiting for the right season to grow.

So before we feed the living daylights out of it, let’s work out what the plant is actually telling us.

First: how long has the plant been in the ground?

This should be the first question.

A plant that hasn't grown much in the three weeks since you planted it is a completely different situation from one that has been sitting in the same spot for two years.

When you transplant something from a pot into the garden, you have changed its entire world.

In the nursery pot, its roots had access to a small, fairly predictable volume of growing media. Water arrived regularly. The root system occupied most of the pot.

Then we take that plant, put it into an enormous volume of completely different soil and expect it to immediately start growing like mad.

Often, it doesn't.

The first priority is establishment.

New roots need to move beyond the original root ball and into the surrounding soil. Until that happens, the plant is still heavily dependent on the relatively tiny root system it arrived with.

This is where the old gardening expression “sleep, creep, leap” comes from.

It isn't a scientific timetable and plants certainly don't all spend exactly one year doing each stage, but the idea is useful.

At first, growth can be slow while the plant establishes.

Then it begins expanding.

Once a good root system is in place and conditions are right, above-ground growth can suddenly accelerate.

That little plant you thought was doing nothing may simply have been building the infrastructure first.

Roots before shoots

Think about what happens when a plant produces a heap of new leaves.

Those leaves need water.

They need minerals.

They need support.

And the larger the canopy becomes, the more water the plant can potentially lose through transpiration.

Producing loads of top growth without enough roots to support it would be a terrible strategy.

So when a newly planted tree, shrub, grass or groundcover doesn't immediately explode with growth, don't assume failure.

Look at the plant itself.

Are the leaves generally healthy?

Is the plant holding its foliage?

Are there fresh buds?

Does it feel firmly anchored rather than loose in the soil?

Can you see any new growth at all, even if it's small?

If yes, patience may genuinely be the main thing it needs.

Plants don't grow at the same speed all year

This catches people constantly.

We read that a plant is “fast growing”, put it in the garden and expect fast growth immediately.

But fast growing doesn't mean constantly growing.

Plants respond to temperature, day length, moisture, soil conditions and their own natural growth cycles.

Many plants put on their strongest growth during the warmer months.

Others perform better in cooler conditions.

Some practically stop when temperatures become very high.

Some slow dramatically in winter.

And some established Australian plants will conserve resources through hot or dry periods rather than pumping out tender new growth that's going to be difficult to support.

So if you planted something just before winter and it appears to have spent three months contemplating life, that doesn't necessarily mean anything is wrong.

Likewise, a plant sitting quietly through a brutal January afternoon may not need a bucket of fertiliser to “get it moving”.

Sometimes the season is telling the plant not to move.

Before you fertilise it, check the soil moisture

This is probably the most important thing you can do.

Not look at the soil.

Not look at the weather app.

Not think about when you last watered.

Actually check the soil.

Push your finger into it or, even better, dig a small hole beside the root zone and see what's happening below the surface.

Because both extremes can stop growth.

If the soil is too dry

Plants need water for photosynthesis, nutrient movement, cell expansion and just about every other process involved in growth.

A plant experiencing water stress may stop producing new growth long before it reaches the dramatic wilting-and-dying stage.

This is especially important with newly planted plants.

The surrounding garden might look damp while the original root ball has dried out.

Or the opposite can happen: you wet the little circle immediately around the stem every day, but the water never penetrates deeply enough to encourage roots out into the surrounding soil.

The aim during establishment is not to keep a tiny patch of soil permanently soggy.

It is to provide enough moisture through the developing root zone to encourage the plant to establish beyond the original pot.

If the soil is too wet

Here's the one that surprises people.

Roots need oxygen.

Healthy soil isn't just dirt and water. There are pore spaces within it that can contain both air and moisture.

If those spaces remain saturated with water for too long, oxygen availability around the roots drops.

And roots that aren't functioning properly cannot support good growth above ground.

This is why an overwatered plant can sometimes look strangely similar to an underwatered one.

It may wilt.

Growth can stop.

Leaves can yellow.

The gardener sees the wilt, assumes the plant is thirsty and adds more water.

Now we have a very unhappy plant standing in a swamp with an owner enthusiastically making the problem worse.

Before watering a struggling plant again, check.

The soil will tell you far more than the calendar will.

Watering every day isn't necessarily helping

There is a huge difference between watering regularly and keeping soil permanently wet.

New plants generally need more attention while establishing because their root systems are still small. But the exact frequency depends on the plant, soil, weather, drainage, exposure and how much water you're actually applying.

A sandy soil on a hot windy site may dry very quickly.

Heavy soil in a sheltered position may remain wet for days.

This is why “water every second day” is such frustrating advice.

Every second day where?

In what soil?

In what weather?

For what plant?

And how much water?

Your plants don't know it's Tuesday.

Check the soil instead.

The plant may be getting the wrong amount of light

Light is food production.

Plants use light to photosynthesise, creating the sugars that fuel growth.

Put a sun-loving plant in heavy shade and it may survive perfectly well for quite some time while producing very little growth.

You may see long, stretched stems reaching toward available light. Foliage can become thinner or greener. Flowering may reduce dramatically.

But there's another side to this.

A plant can also receive too much sun for the conditions it prefers.

“Full sun” on a mild coastal site is not necessarily the same experience as full western sun against a heat-reflecting wall in inland Australia.

A plant constantly dealing with excessive heat and water loss may devote more resources to survival than growth.

So don't just ask:

Does this plant need sun or shade?

Ask:

What kind of sun is it getting here?

Morning sun?

Filtered light?

Six hours of open sun?

Blazing western sun with reflected heat from concrete?

They're very different environments.

Your soil might be compacted

Sometimes there's plenty of water and plenty of nutrients sitting in the soil.

The roots just can't get to them very effectively.

Compacted soil has reduced pore space, which affects both water movement and air availability and can make physical root growth more difficult.

This is particularly common around new homes, construction areas and places that have had machinery or repeated foot traffic over them.

A beautiful layer of fresh topsoil can also hide heavily compacted material underneath.

The plant begins growing into the nice planting hole, reaches the surrounding compacted soil and suddenly expansion becomes much harder.

This is one reason we don't want to create a tiny luxurious potting-mix bathtub in the middle of terrible soil.

The goal is for roots to establish into the surrounding soil, not spend the rest of their life inside the hole you dug on planting day.

Check how deeply you planted it

This sounds almost too simple to matter.

It matters.

Planting too deeply can bury parts of a plant that weren't meant to be underground and can affect oxygen availability around the crown or trunk.

With many trees and shrubs, you don't want to bury the stem simply because you've dug a heroic hole.

Look at the level the plant was growing at in its container and use that as your guide unless that particular species has different planting requirements.

And be careful with mulch afterwards.

Mulch is fantastic.

A volcano of mulch piled against a trunk is not.

Keep it over the root zone while leaving breathing room immediately around stems and trunks.

The roots might still be shaped like the pot

This is particularly relevant when planting older, pot-bound plants.

Roots grow where conditions allow them to grow.

If a plant has spent too long in a container, roots may begin circling around the inside rather than growing outward.

Put that root system straight into the ground without addressing severe circling and those roots don't magically receive a map showing them the way out.

This is one reason the biggest plant on the nursery bench isn't automatically the best buy.

A smaller, healthy plant with an active root system can establish incredibly well once planted into suitable conditions.

It's also one of the reasons we love growing and selling tubestock.

You're not paying to transport a giant pot full of growing media around Australia. You're buying a young plant and giving its root system the opportunity to establish in the soil where it is actually going to live.

Small at planting doesn't necessarily mean slow in the long run.

There may be a tree stealing its lunch

You've prepared the soil.

You've watered beautifully.

You've chosen the right light.

And the new plant still sits there doing nothing.

Look up.

Established trees can create enormous competition below ground.

The visible trunk is only part of the story. Roots extend through the surrounding soil taking up water and nutrients, and a newly planted little shrub underneath can find itself competing against a root system that has been there for decades.

This is why planting under established trees can be surprisingly difficult even when the shade level seems perfect.

It isn't only about light.

Root competition matters too.

Some plants handle that environment far better than others, which is why choosing plants specifically suited to dry shade or under-tree planting can make such a difference.

Should I fertilise a plant that isn't growing?

Maybe.

But not automatically.

Fertiliser supplies nutrients.

It does not fix poor drainage.

It does not fix compacted soil.

It does not create sunlight.

It does not correct a plant buried too deeply.

And it definitely doesn't repair roots sitting in permanently saturated soil.

If the actual problem is environmental, adding more fertiliser can be useless and in some situations can create another problem.

First work through the basics:

Is the soil moisture right?

Is drainage okay?

Is the plant getting suitable light?

Is it the right season for active growth?

Is it newly planted?

Is there obvious pest or disease damage?

Is the root zone healthy?

Then consider nutrition.

Plants absolutely need nutrients, but more fertiliser does not automatically equal more growth.

And different plants have different nutritional requirements.

Australian natives are a perfect example. People sometimes hear “don't fertilise natives” and interpret that as “Australian plants don't need nutrients”, which isn't true.

Plants need nutrients.

But some Australian plants, particularly members of the Proteaceae family, can be sensitive to high levels of phosphorus.

So the answer isn't “never fertilise natives”.

It's use an appropriate fertiliser for the plant you're growing and follow the directions rather than assuming more must be better.

Soil pH can affect what a plant can actually access

Here's another strange bit of gardening.

Your soil can contain a nutrient and your plant can still struggle to use it.

Soil pH affects nutrient availability.

At different pH levels, some nutrients become more or less available to plants.

That means a plant showing signs that look like nutrient deficiency isn't always growing in soil that contains absolutely none of that nutrient.

The chemistry of the soil can influence whether the roots can access it effectively.

This is why throwing handful after handful of fertiliser at an unexplained problem isn't great diagnosis.

Sometimes a soil test tells you far more than another bag of fertiliser.

Is something eating the new growth?

Sometimes your plant actually is growing.

Something else is just eating the evidence.

Look closely at the growing tips.

Caterpillars, beetles, snails, slugs and other pests can target soft new growth, sometimes almost as quickly as the plant produces it.

If older leaves remain but every fresh tip seems damaged or disappears, have a proper inspection.

Look underneath leaves.

Look along stems.

Look around the plant at night if you suspect snails or slugs.

Don't immediately spray everything with whatever is in the shed.

Find out what's actually doing the damage first.

A garden is supposed to contain insects.

Not every bug requires an eviction notice.

Sometimes pruning can actually encourage bushier growth

Plants have growing points, and removing a growing tip can alter the way some plants branch.

This is why strategic pruning can turn certain young shrubs from tall, sparse plants into denser, bushier ones.

But this does not mean every slow-growing plant should immediately be attacked with secateurs.

Different plants respond differently to pruning.

The important lesson is that growth isn't only about speed.

Shape matters too.

If you're trying to establish a hedge, for example, the fastest possible vertical growth isn't necessarily the goal.

You want branching and density as well.

Sometimes letting a plant race upward untouched gives you height but not the thick screen you imagined.

The grass might be winning

Grass is astonishingly good at competing.

If you've planted a young tree or shrub directly into lawn and allowed grass to grow right up to the stem, the plant is sharing its immediate root zone with thousands of grass roots competing for water and nutrients.

Creating a clear, mulched area around new plantings can reduce that competition while the plant establishes.

Just remember our earlier rule:

Mulch around the plant.

Not up the plant.

No mulch volcanoes.

“Fast growing” is relative

This phrase causes so much disappointment.

A fast-growing tree and a fast-growing groundcover aren't being judged on the same scale.

Neither are two plants growing in completely different climates.

Growth rates quoted for plants are usually indicative, not contractual agreements signed by the plant.

Climate, soil, rainfall, irrigation, nutrition, exposure, age and competition all affect what actually happens in your garden.

A plant described as fast growing still needs suitable conditions to grow fast.

Put it somewhere it hates and it may become the world's fastest-growing plant at doing absolutely nothing.

Tubestock can surprise you

One of the most common concerns people have when buying plants online is size.

The plant arrives and it's small.

Surely a bigger plant would establish faster?

Not necessarily.

Advanced plants certainly give you more immediate visual impact, and there are situations where that's exactly what you want.

But young plants have an enormous advantage: you're giving them the opportunity to establish their root system in their permanent environment relatively early in life.

Healthy tubestock planted into suitable conditions can establish quickly and, depending on the species and conditions, can sometimes make up the apparent size difference surprisingly fast.

When you're planting large areas, hedges, groundcovers or mass plantings, this becomes particularly useful because you're spending your money on plants, rather than enormous pots and freight.

Judge the plant by its health, root quality, suitability and eventual performance.

Not just how impressive the pot looks on planting day.

Why has my plant grown for a while and suddenly stopped?

Now we're asking a different question.

If a plant was actively growing and then stopped, think about what changed.

Did the weather become hotter?

Did winter arrive?

Has rainfall changed?

Did the irrigation system stop working?

Has a nearby tree grown and increased shade?

Has the soil become waterlogged?

Did you recently fertilise?

Was the plant pruned?

Has something started attacking the new growth?

This is where gardening becomes detective work.

Plants don't generally decide on a Wednesday that they've lost interest in personal development.

Something changed.

Your job is to work out what.

Why are my plants growing but not flowering?

Growth and flowering are related, but they're not the same thing.

A plant can produce masses of beautiful foliage and very few flowers.

Light is one of the first things to investigate.

Many flowering plants need sufficient light to flower well.

Nutrition can also play a role. Excessive nitrogen can encourage lush leafy growth without necessarily improving flowering.

Age, pruning timing, temperature and the plant's natural flowering cycle matter too.

This deserves an article of its own because there are a surprising number of reasons a perfectly healthy plant can refuse to flower.

But if your plant is growing beautifully and simply isn't flowering, don't treat it like a plant that isn't growing at all.

Those are two different problems.

When should I actually worry?

A plant doing very little isn't necessarily in trouble.

A plant declining is different.

Pay attention if you're seeing things such as progressive leaf loss, widespread yellowing, dieback moving down stems, soft or rotting tissue around the base, severe wilting that doesn't recover, obvious pest damage, roots rotting or a plant becoming increasingly loose in the ground.

That's when you need to investigate properly.

And sometimes, despite our best efforts, the answer is that the plant simply isn't suited to that spot.

That isn't gardening failure.

It's information.

Gardens are full of little experiments.

The trick is learning from them rather than repeatedly buying the same plant and putting it back into the same conditions that killed the last three.

Before you replace it, do this

If your plant isn't growing, work through this little investigation before you pull it out.

Check the soil moisture. Dig down rather than judging the surface.

Think about how long it has been planted. A newly planted plant may still be establishing.

Consider the season. Is this actually an active growing period for that plant?

Look at the light. Has the position got enough — or too much?

Check drainage. Does water sit around the roots after rain?

Look for competition. Grass and established tree roots can make life difficult for new plants.

Inspect the growing tips. Is something eating the new growth?

Check the planting depth and mulch. Make sure the stem or crown hasn't been buried.

Then think about nutrition.

Not the other way around.

The most important question isn't “How do I make it grow faster?”

It's:

“What does this plant need to grow well here?”

That little change in thinking will make you a much better gardener.

Because gardening isn't really about forcing plants to perform.

It's about creating the conditions where they can.

Get the plant right.

Get the position right.

Get the soil and water reasonably right.

Give the roots time to establish.

And then sometimes the best thing you can possibly do is stop standing over the poor thing asking why it hasn't doubled in size since Tuesday.

Plants are working on plant time.

Annoying.

But probably healthier than the way the rest of us live.