Zinnias are usually tough and do well in most conditions. But they can still struggle and even die if not treated properly.
You might see your zinnias leaves drooping, the flowers wilt or the leaves turn brown. Whatever happens there are some common reasons that your zinnias might be struggling.
I’ve managed to save and revive my zinnias when they’ve had problems so I’m going to go through the process of what to do and how you can bring your zinnias back to life.
Step 1: Diagnosing the Problem
Before you jump to any conclusion it’s best to actually identify what the cause (pun intended) of the issue is. Then you’ll know exactly what to do to fix it.
So these are some of the most common problems you can get with zinnias:
Common Causes:
- Over or underwatering
- Poor soil drainage
- Fungal diseases (powdery mildew, leaf spot etc)
- Pest infestations (aphids, spider mites)
- Stress from the heat or frost
- Nutrient deficiencies
- Natural aging
Step 2: Adjust Watering Habits
Overwatering and underwatering are probably the most common problem that affects zinnias. They don’t need too much water but they do need to be consistently moist to stay healthy.
If you overwater your zinnia it will get root rot and underwatering it will mean it wilts and dries up.
But you can get the balance right:
Watering Tips:
- Don’t water too often but when you do, do it deeply. You want the soil to be damp down to about 6 or 8 inches.
- Before you water again check how moist the soil is by feeling the top few inches of it.
- Water at the base of the plant so you don’t get the leaves wet. Doing so can result in fungus growing.
- It’s best to water in the morning as the water won’t evaporate in the heat and will let your zinnias absorb more of it.
Step 3: Soil Drainage and Quality
Zinnias like soil that drains well. If you think yours might have poor drainage then you’ll want to either help or change it.
Clay heavy soil that is compacted can suffocate the roots. Sandy soil will let the water drain through too fast and stop your zinnias from being able to absorb it and the nutrients it needs.
Adding compost or manure will help with the drainage, texture and nutrients in the soil.
What to Do If Root Rot Occurs:
- Dig up your zinnias and check the roots. You’ll know if they’re healthy as they’ll look white and be firm.
- If some roots are mushy or brown trim them and replant the zinnia in fresh soil that drains well.
- You can some perlite or grit which will improve the drainage and stop any root rot in the future.
Step 4: Dealing with Pests and Diseases
Zinnias also can be affected by infections (like powdery mildew), bacterial issues (leaf spot) and pests.
You’ll notice powdery mildew as it covers the leaves with a white powder. Bacterial spots look like gray or brown blotches.
The usual cause of these types of diseases are not enough air getting to the plant or too much water on the leaves.
How to Treat Fungal Infections:
- Remove the affected leaves so it doesn’t have a chance to spread.
- Use something like neem oil (so a fungicide) to treat it. Always follow the instructions on the label.
- Make sure there is good air flow around your zinnias. They need to be spaced apart and not crowded. Also don’t water them from overhead.
Pests are also a problem. The likes of aphids and spider mites will suck sap from the leaves and this leads to wilting.
You should try to check your plants regularly for pests. If you find any then use insecticidal soap or neem oil. Although if the pests infestation is bad you may have to prune the areas that are affected.
Step 5: Managing Temperature Stress
Zinnias may love the heat but if it gets too hot or cold they will get stressed. Frost in particularly will cause some major problems, making the flowers turn brown.
If your zinnias have been hit by a frost then unfortunately you might not be able to save them.
Frost and Heat Management:
- When it gets extremely hot then give your zinnias some shade using a cloth. Or if they’re in pots you can move them to somewhere that gets less sun and heat.
- If you’re somewhere colder then cover your zinnias with frost cloths or bring them indoors when it gets below freezing.
Step 6: Feeding and Fertilizing
Zinnias need the right nutrients to really do well. If yours are turning yellow or brown that can be a sign of not enough nutrients.
Not enough nitrogen is especially a problem and will cause yellow leaves. And a lack of phosphorus or potassium can also cause browning.
Correcting Nutrient Deficiencies:
- Use a balanced fertilizer once every couple of weeks during the growing season.
- Use organic compost to add some nutrition.
- Check your soil’s pH and if you have to alter it. Zinnias like the soil to be slightly acidic to neutral pH (6.0-7.0).
Step 7: Deadheading and Pruning
As zinnias age the flowers can fade and become scraggly. As this happens those flowers will continue to drain energy from the plant.
To get new flowers blooming the deadhead the spent flowers.
Deadheading Tips:
- Cut off the dead flowers just above a healthy set of leaves.
- Don’t be afraid to prune heavily. Cutting it back will get better growth and more flowers.
Step 8: Rejuvenating Severely Affected Zinnias
If your zinnia is really struggling then you may have to take some drastic steps to save it:
- If it can’t be saved then collect the seeds from the dying flowers and replant them next season.
- If your zinnias are too affected by pests or waterlogged then uproot them, trim the roots or leaves/flowers that are damaged and replant them in fresh soil.
- Watch the recovery closely and give it the right water, light and nutrients.
Step 9: Preventative Measures for the Future
Once you’ve saved your zinnias you don’t want them to end up the same again. So prevent them from becoming unhealthy is important
Ongoing Care Tips:
- Use a moisture meter to keep check of how damp it is and so you can make sure you’re not overwatering.
- Plant your zinnias somewhere that they will get at least least 6 hours of sunlight every day. The spot should also have some afternoon shade if you’re in a hotter climate.
- Keep your garden clear of dead plant material as it can have pests and diseases loving in it that will spread to your zinnias.
- Fertilize sparingly but don’t overdo it. Too much ferilizer can lead to too much nitrogen which and this will result in less flowers but more leaves.
Final Thoughts
Reviving a zinnia takes some time and paying close attention to the details. You have to show some patience or you can forget about recovering them.
But if you figure out what they really need and react fast enough then there’s absolutely no reason you can’t save a struggling zinnia. Give them the right care and they can flourish again and forgive any problems they may have had.
