Disorders
Blossom end rot
Blossom end rot produces dark patches on the bottom of tomato fruits – as well as peppers and aubergines. This plant disorder is mostly caused by irregular watering.Symptoms
Roughly circular black or brown patches at the bottom (blossom end) of the fruit
As they age, the patches may become sunken
What is blossom end rot?Blossom end rot is ...
Boron deficiency
Boron is a micronutrient, needed by plants in small amounts. A deficiency can cause poor and stunted growth and a range of other symptoms, depending on the plant.Symptoms
Stunted and poor growth
Leaf tip browning and dieback
A range of other symptoms, depending on the plant
What is boron deficiency?Boron (B) is one of the micronutrients or ...
Calcium deficiency
Calcium deficiency isn’t common, and can be difficult to diagnose, but is responsible for two main disorders – blossom end rot in tomatoes and bitter pit in apples.Symptoms
Localised tissue necrosis and death
Brown, dead margins on young leaves
Leaf curling
Stunted growth
Blossom end rot – roughly circular black or brown ...
Cold and frost damage
Frost and cold weather can damage numerous plants, but especially tender plants that can’t tolerate low or freezing temperatures and tender, new growth in spring.Symptoms
Black scorching and brown patches on leaves, especially new and young growth
Initially, this may only appear on the leaf edges, but soon spreads
Totally collapsed and ...
Drought and underwatering
Nearly all plants need a constant and regular supply of water for their roots to absorb. If this is interrupted plants start to wilt and can eventually die.Symptoms
Wilted leaves and top growth
Few or no healthy white roots
Plants killed
What are drought and underwatering?Nearly all plants need a constant and regular supply of water for their ...
Graft failure
Many trees, shrubs and climbing plants are grafted onto a rootstock – and sometimes that graft can fail. This leads to the grafted variety dying back or dying.Symptoms
The plant starts showing signs of poor growth and gradual or very sudden deterioration or dieback
The rootstock and grafted variety (scion) are partly or completely separated
...
Iron deficiency
Lime-induced Chlorosis
Iron deficiency, sometimes referred to as lime-induced chlorosis, is a plant disorder that causes the leaves to turn yellow, between the veins, sometimes with brown edges.Symptoms
Leaves turn yellow between the veins, sometimes with brown edges
Young leaves may appear bleached
What is iron deficiency?Iron (Fe) is one of ...
Lichens
(Numerous species)
Lichens add interesting colours and patterns to hard surfaces, for which they are often encouraged. But people panic when they’re found growing on plants.What are lichens?Lichens are non-parasitic, plant-like organisms; they are, in fact, composite organisms – a species of fungus growing with a species of algae and ...
Magnesium deficiency
Magnesium deficiency is a plant disorder that causes the leaves to turn yellow between the veins, sometimes with reddish tints. It also results in early leaf fall.Symptoms
Leaves turn yellow between the veins, sometimes with reddish or purple tints
Early leaf fall
What is magnesium deficiency?Magnesium (Mg) is one of the secondary ...
Nitrogen deficiency
Nitrogen deficiency is a common plant disorder in poor soils or after excessive winter rain. It results in yellow or yellowing leaves and spindly or stunted growth.Symptoms
Yellow or yellowing leaves, sometimes with pinkish tints
Spindly, yellowish plants
Stunted growth
What is nitrogen deficiency?Nitrogen (N) is one of the macronutrients, ...
Phosphorous (phosphate) deficiency
Phosphorous (phosphate) deficiency is a plant disorder that results in changes in leaf colour – yellow or purple – smaller leaves and slow, sometimes stunted, growth.Symptoms
Leaves turn a dull yellow or purple/red colour
Poor, slow growth
Often stunted growth
Smaller and/or fewer leaves
Poor root growth, smaller root systems
What ...
Potassium (Potash) deficiency
Potassium (potash) deficiency is a common plant disorder that mainly results in discoloured leaves, including brown edges, as well as poor flowering and fruiting.Symptoms
Yellow or purple colouring in the leaves
Leaves with brown edges and curled tips
Poor flowering
Poor fruiting
Plants sensitive to cold weather
Reduced resistance to plant ...
Reversion
Some plants – particularly those with variegated leaves or other colours – produce stems with all-green leaves. This is called reversion, and these stems should be removed.Symptoms
Plants with variegated or otherwise coloured or shaped leaves produce stems with “normal” colours or shapes
What is reversion?Some plants ...
Suckers
Trees, shrubs and climbing plants that are grafted onto a rootstock often produce shoots from the rootstock – known as suckers. These should be removed.Symptoms
Stems growing from below ground level on grafted plants
They may be produced singly or in profusion
They may be produced at the base of the plant – or some distance away
...
Vegetable bolting
It’s so frustrating, having grown your vegetables perfectly for months, for them to bolt – or go to seed prematurely – before they’re ready to harvest, and may be unusable.Symptoms
Vegetables, often suddenly, produce flower heads before they’re ready to harvest
The crop puts its energy into the flowers and seeds, ...
Waterlogging, flooding and overwatering
While all plants need a constant and regular supply of water for their roots to absorb, the vast majority won’t grow in soil or compost that is overly wet or waterlogged.Symptoms
Leaves turn yellow and drop prematurely
Shoots start to die back and the whole plant starts to wilt
Bark may start to peel off stems
Herbaceous plants fail to ...
Wind damage
Apart from the obvious damage when trees are blown over, strong winds can also cause damage to a wide range of plants by shredding and shrivelling their leaves.Symptoms
Brown or black, scorched leaves, either on their edges or the whole leaf, turning dry and brittle
Damage worse on windward side of the plant
Ripped or torn stems, shoots and ...