Hebes are beautiful plants with ornamental leaves and flowers that are and popular with bees and other pollinators.
As a beginner gardener, it can sometimes be disheartening when the plants you have nurtured from seed or bought from a garden centre lose their health and begin to falter.
So if you have asked the question “Why Is My Hebe Going Brown?” then read on for answers and solutions.
Hebes can suffer from Root Rot, Leaf Spot Disease and Downy Mildew. They can also be affected by incorrect water levels, pests or being in the wrong location.
Root Rot
Root rot is a common problem that can affect many plants and is caused by a fungus that decomposes the root system.
The conditions for this fungus to grow can come about if the soil around the Hebe root ball becomes too waterlogged.
This can happen for a number of reasons.
If you have overwatered the plant (see below) to a point where the soil is saturated then this may occur, commonly seen when the plant is in a container with poor drainage.
If your soil type is naturally water retentive then even a small amount of water or rain can accumulate around the roots and cause the fungus to grow.
How to fix:
- Uproot the plant and look at the root system. If it is already all rotted then unfortunately it is unlikely your plant will survive and it will be best to pull it up and dispose of it (not in the compost heap). If there is still a majority of roots that are unaffected then wash the roots under clean water and remove the affected parts.
- Dispose of the soil around the root ball (not in the compost heap) and make sure you wash all containers and tools.
- Repot or replant the Hebe using fresh soil with some grit to aid drainage.
- If planting in containers make sure they have adequate drainage holes, add more if necessary.
- You can place a crock (broken pot) over the drainage holes to make sure they do not become clogged with soil.
- Consider planting your Hebe into the ground instead so it will benefit from natural drainage.
Septoria Leaf Spot Disease
This is another fungus that grows in similar conditions to Root rot when the climate around the plant is too moist, or leaves have been splashed when watering causing infected matter from the soil to land on them.
Leaves become covered in small black spots which then increase in size and turn brown or grey, eventually covering the majority of the leaf which yellows and then falls into the soil, passing on further spores.
How to fix:
- If caught early when the leaves are only slightly affected, it is possible to just carefully strip the affected leaves from the plant using gloves and cleaning all containers and tools.
- Separate the plant from others around it while it recovers to prevent further plants becoming infected.
- Clear accumulated debris around the base of the plant, creating better air circulation.
- Replace the top layer of soil around the plant, or add mulch to form a barrier for the spores.
- When watering plants, take care not to splash water up onto the foliage.
- Treat with neem oil or a baking soda solution (1 teaspoon of baking soda to 1 litre of water).
- If plants are badly affected and multiple leaves have dropped, it may be best to remove the infected plant and dispose of the material entirely, making sure not to add to the compost heap, and thoroughly wash all containers and tools.
Downy Mildew
This common fungus can affect many plants including roses, buddhlias, Verbena and Laurel.
Here is a great fact sheet from the Horticultural Development Company that covers lots of information regarding Downy Mildew.
The conditions for growth of this fungus are created in warm and humid conditions, or when the plant has been watered from above and left wet, with inadequate air circulation for the leaves to dry fully.
The first indication is leaves turning yellow and deteriorating.
This can progress to curling leaves and sometimes a furry covering on the underside.
Leaves then die and fall. This can lead to the degradation and death of the entire plant.
How to fix:
- Don’t crowd plants together especially if conditions are warm and humid.
- Try to keep good airflow around the plants.
- Don’t water from overhead if possible, water gently at the base of the plant.
- Keep a look out for Downy Mildew by regularly checking the underside of leaves
- Act quickly if you see the signs, remove the infected parts of the plant and dispose (not on the compost heap). This may be enough to salvage affected plants if this can be done in time.
- If plants are badly affected and multiple leaves have dropped, it may be best to remove the infected plant and dispose of the material entirely, making sure not to add to the compost heap, and thoroughly wash all containers and tools.
Overwatering
As mentioned above, overwatering can cause further problems for your Hebe by creating the conditions require for fungus to thrive, but even just providing too much water can affect Hebe plants negatively.
Hebes are naturally found in scrub lands and do not require a rich soil.
They like free draining conditions and are quite drought tolerant, which makes them an ideal border plant for a low maintenance garden.
How to fix:
- It can be tempting to keep watering new plants to make sure they become established, but with Hebes it is not necessary to water every day. Water new plants well once a week if in the ground for two weeks.
- If conditions are extremely dry follow this by watering once every fortnight, otherwise natural rainwater will probably be sufficient.
- If in a pot, stick your finger into the soil and only water if the top 5cm (2 inches) is dry.
- If your soil is particularly heavy and moisture retentive like peat, add some grit to improve drainage.
- You can create a little drain just by forming the soil into a channel that runs away from the plant, so that the water does not sit around the root ball.
Underwatering
Although Hebes are fairly drought resistant they do of course require some water to thrive, especially when they are flowering.
Watering well once every two weeks should be sufficient for a Hebe in normal conditions during a warm summer, for example in a partially sunny spot with well draining soil.
You should not need to water during the other seasons.
How to fix:
- If it is a newly planted Hebe you can give it a little extra water just so it can get established. Water well once a week for two weeks, then revert to once every two weeks during a dry summer.
- If conditions are particularly warm and dry, and if you have very poor soil you can mulch around the base to provide some nutrients and water retention.
- If you tend to forget when you last watered, then it’s a good idea to keep a diary to remind you.
Incorrect Position in the Garden
Almost all successful planting relies on the “right plant, right place” ethos and Hebes will suffer if they are in the wrong place in your garden.
They do need a reasonable amount of light and will not like to be in an exposed windy location.
How to fix:
- If you have bought your Hebe in a pot, or are ready to transplant Hebes grown from seed then don’t plant them straight away but rather position them in different points around the garden to see where they fare best.
- If your Hebe plants are already in the ground in an unsuitable position then you can move them to a more appropriate spot. They are fairly hardy and won’t mind being moved, just try not to do it multiple times.
- It is best to move plants in the morning while they have their maximum water content. You can also water the plant first. Then dig them up carefully, making sure to keep the root ball intact and transplant them to the new spot. Water in well.
Pests
Hebes do not tend to attract too many pests unless they are unhealthy.
Two common types of insect that can feed on Hebes however are caterpillars and vine weevils.
Caterpillars are reasonably easy to spot and can be picked off as they will just eat the leaves.
Vine weevils on the other hand can not only eat the leaves (this is the adults during spring and summer) but their grubs eat the roots during the autumn and winter months.
This will cause the plant to wilt and discolour.
If your Hebe is browning during this time and you have eliminated other possible causes then you may have a vine weevil infestation.
How to fix:
- Keep an eye on Hebes throughout the autumn and winter, especially those in pots.
- If you see signs of adult vine weevils earlier on in the year then there is the possibility you will have grubs later on.
- If a plant looks to be suffering then dig it up and check the roots. If you do have grubs then remove the Hebe, wash the roots clean and replant in a different pot or area.
- Encourage hedgehogs and other wildlife such as birds and frogs for natural pest control.
Final Thoughts
On the whole they are hardy and drought tolerant and so perfect for a low maintenance garden, however it is good to prune them regularly and protect them from frost.
If your Hebe is struggling and turning brown then it will likely be one of the reasons above.
Caught early these issues can be fixed and your plant saved!
Check out more articles coming soon if you are having similar problems with other common garden plants.
Together we can maintain our garden heavens for years to come.
