Lavender (Lavandula) is a beautiful, aromatic plant native to the Mediterranean which many gardeners incorporate into their landscape, sometimes with dismaying results. If you notice your lavender plants dying, you’re probably wondering why and how to revive lavender.
Why is My Lavender Plant Dying?
If you’ve noticed your lavender plant is looking a bit peaked, the first order of business is to identify the cause. Lavender plants can be a bit persnickety. For one thing they require well-draining soil with a pH of 6 to 8. A soil test will help to determine if the pH needs adjusting. To raise pH, amend the soil with limestone.
As lavender hails from the Mediterranean, this plant needs plenty of sun; six to eight hours per day. New plants are not yet able to tolerate the heat, however, so plant them in early to mid-spring so they have time to acclimate before the hot temps of summer.
Also, some people may think their lavender plant is dying when in fact it is dormant. Dormancy happens when temps cool and sunlight is less available. Dead lavender will have no sign of green but instead the branches will be brown and hollow.
Temperature is another reason why your lavender plant may be dying. Snow doesn’t affect mature lavender plants, but chilly temps will. Mature lavender tolerates lows of 10 degrees F. (-12 C.); however, newly planted lavenders may succumb to temps below 40 degrees F. (4 C.) at night.
Lavender in Pots Dying
Growing lavender in pots has its own set of special considerations. If you have lavender in pots dying it may be because the plant is over or underwatered, the soil is inconsistent with the plant's needs, the plant is too little, getting too much sunlight, or the plant may need to be fertilized.
Again, cold temperatures may affect potted lavender. It is a good idea to protect potted lavender when temperatures dip by moving the plant into a garage, covering the plant, or mulching heavily.
Both potted lavender and those in the earth can be affected by over or underwatering. Overwatered lavender may have yellowing leaves, initially on the lower leaves. Dropping, a rotting odor, and of course sodden soil are also indicators of an overwatered lavender dying.
Underwatered lavender will droop and the soil will feel completely dried out. To correctly water potted lavender, soak the soil well and then allow the top inch (2.5 cm.) to dry out completely before watering again.
Additional Reasons for a Dying Lavender Plant
Root rot is a common problem caused by overwatering that results in a lavender plant dying. If you suspect root rot you must act quickly to save the plant. Remove the plant from the soil and prune off any affected roots. Then replant the lavender in well-draining soil.
Insects can also cause a lavender plant to die. Spittlebugs and froghoppers both suck the sap from plants. You can detect them by observing the white, frothy blobs that appear on the stems and leaves of infested plants.
The four-lined plant bug (FLPB) is another sucking insect that feeds on new leaves and stems from late May to early July. Infested leaves end up being spotted with uniform white or gray dots. Generally, the damage done here is more ornamental than deadly.
Disease can also affect lavender. Septoria leaf spot is caused by a fungus that weakens plants in the late summer to early fall. It is fostered by humid, wet conditions. Another symptom of Septoria leaf spot is round spots on the leaves. This fungal disease is spread by wind.
Lavender shab is another fungal disease which results in twisted, brown stems along with tiny black dots on the stem. This disease is easily transmitted so pull out infected plants and destroy them.
How to Revive Lavender
- If root rot is suspected, prune out infected roots and replant the lavender in well-draining soil.
- Be sure your lavender, potted or otherwise, receives six to eight hours of sun.
- Water deeply but wait until the top inch (2.5 cm.) of the soil is dry until watering again. Use a soaker hose or water at the base of the plant to keep the foliage dry to minimize fungal disease.
- Lavender naturally becomes leggy with open, woody regions at the center of the plant. Prune back the plant by one third to one half before new growth starts.
- Test your soil. The ideal pH for lavender is 6 to 8. Amend with limestone to raise the pH.
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Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.
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