What causes Lavender plants change color?
The most frequent causes that lavender leaves turn yellow is due to excessive nitrogen levels in the soil, or over the watering of lavenders and lavenders which are planted in soil that drains too slow.
If the lavender displays an orange-brown or yellowish foliage, with an general wilting or drooping appearance, it means that the lavender is either watered or is in slow draining soil, and not over watered (lavenders are drought-resistant).
The lavender foliage is yellow, and appears leggy with a few flowers suffers from soil that is heavy in nitrogen.
Find out the reason why your lavender has turned yellow and the best way to fix it…
Causes of Lavender Turning Yellow Excessive Nitrogen and Over Fertilizing
One of the main reasons why lavender turns yellow is due to excessive nitrogen levels in the soil.
Nitrogen is a nutrient which is needed by all plants, however excessive nitrogen in soils will cause a lavender that’s lopsided, messy in appearance, and has leaves which turns yellow.
Lavenders are indigenous in their native Mediterranean area of Europe which is where they thrive in sandy, nutrient-poor soils.
To ensure that your lavender plants are healthy and produce flowers, you must recreate the conditions.
A soil that is too fertile requires amendment with sand or grit , and you must avoid applying fertilizers on lavenders that are already established. It’s counterintuitive however, the more fertile your soil is, the more likely you are to get a lavender with yellow foliage, but no flowers since lavenders are designed to work in soils with low fertility and thrive in these conditions.
Sand and grit don’t provide much nitrogen or nutrients to soils, so it is possible to offset the richness of nutrient-rich soils by amending them with these substances. Sand and grit can give the soil the ideal structure that allows for rapid drainage, which lavenders need to prevent diseases like roots rot.
It is recommended to amend the soil using sand or grit prior to planting lavenders in pots or gardens However, you must amend the soil with urgency if your lavender’s leaves are becoming yellow.
If you have lavender already in the ground using a fork, lift the lavender from the soil, while protecting the most roots you can. The proportion of sand to soil should be between 30% sand to 70 percent soil.
(If you are in the area of clay soil, I suggest you read my post on the best way to prep clay soil to grow lavender since clay soils need significant amounts of amending).
If you adhere to the most effective practices for care the lavender will recover and bloom next year If you alter the soil and avoid using excessive fertilizers.
Yellow Lavender Over Watering
Overwatering is probably the most frequent mistake made when taking care of lavenders. The lavenders are adapted to the dry, harsh conditions of the Mediterranean summer, and thus require little or no water.
The lavenders that are over watered have an effected, drooping appearance and leaves that are either brown or yellow. Many people confuse the appearance of wilting as being caused by being under-watered and can exacerbate the issue by overwatering the lavender even more.
- Established lavenders in the outdoors do not require any additional watering in climates with temperate temperatures but only during times of severe droughts in summer. They can get more than enough water through rainfall.
- Potted lavenders require extra attention since pots tend to dry out faster (see my guide on the proper watering of the pots of lavender plants).
- In dry climates, lavenders typically only require irrigation once every two weeks during the spring and summer.
- Indoor lavenders only require irrigation once every 2 weeks (see my guide on the watering of indoor lavender guidelines).
- The lavenders don’t typically require any water in winter and fall However, if you keep your lavender plants inside during winter, then watering them once every 4-6 weeks should suffice (assuming the soil is well-draining).
To treat the yellowing of lavender after it has been over-watered The solution is to simply cut off the watering for your plant at least 3 weeks, and allow the soil and roots to dry out. But some lavenders simply will do not recover from the constant over-watering and will eventually end up dying, so preventative measures are better than cure in this instance.
The most common problem with overwatered, yellowing lavenders are a problem caused by poor drainage soils. Both of these aspects need to be considered in the process of reviving a plant that is brown or yellow in color.
If you live living in a temperate, rainy climate, I would suggest plant lavenders in pots since they are more aerable and the pots can be moved to a covered area or even towards the rain shade of a building during the event of persistent rain.
The majority of lavender species do very well in pots. Check out my guide to the care of lavender pots for great suggestions.
The humidity level is another thing to take into consideration when your lavender is beginning to turn yellow. The lavenders prefer to keep their foliage and roots dry (although they are tolerant of the coastal climate).
Lavenders can struggle to grow and bloom in humid climates, however there are some things that you could do increase the chances of success:
- It is essential to place your lavenders at least 3 feet from each other and put them in an area that has air circulation. A breeze on occasion can aid in keeping the foliage as well as the soil dry.
- Lavenders require full sun (at minimum six hours throughout the day). The more sunlight lavenders get, the healthier the plant will be , and less susceptible to yellowing and disease.
- One of the best tips I learned from commercial lavender cultivators from California is to utilize white stones or pebbles, as an alternative to a groundcover. The white stones are able reflect light back onto the lavender’s foliage that creates its own microclimate on hot days. This keeps laurel dry and reduces the growth of weeds and boosts the harvest of lavender in terms of blooms and oils.
- The potted lavenders permit you to put your lavenders in the most sunny spot and, ideally, in a place which is far from the source of humidity. Place lavenders in a patio and than in a place with lots of plants is more beneficial to reduce the yellowing of lavender.
The addition of materials such as grit or sand to the soil can also aid in keeping the roots of the lavender dry, which is an issue in humid regions. Dryer foliage means healthier plants that are less likely to become yellow.
Poor Drainage of Soil Brown/Yellow with a Drooping Appearance
Lavenders naturally thrive in sandy soils that drain quickly and doesn’t retain water for long, unlike soils that have a high organic content.
The yellow (or the brown) foliage is a sign of root rot, a disease. The plants prefer the soil to dry out between watering periods since the roots are not able to tolerate the constant moist soil.
To grow lavenders successfully, you need to replicate the conditions of the soil in their home region of Mediterranean. The soil in which lavender grows naturally in countries such as Spain, Italy and Southern France is extremely sandy, and occasionally gravelly.
This lets water drain into the soil quickly, so that the root of the lavender will remain somewhat dry and remain healthy.
The only thing you have in order to increase the drainage of your pots or garden soil is to alter the area you are planting in by adding sand. In the majority of gardens, 30% sand and 70 percent soil is a great ratio to strive at. In poor draining soils it is possible to raise this ratio to 50:50.
The soil should be amended using grit or sand to a depth of approximately 18 inches to allow for the root system of the most extensive lavenders once they are fully mature.
You can till or dig the area, adding sand or grit , and then plant the lavender again.
If your garden is particularly low-lying and has naturally moist soil, you can transfer your lavenders into pots or make raised beds to create the ideal soil conditions to grow lavender.
If you mix in the sand grit , you will be able to replicate the ideal Mediterranean conditions for growing and the lavender’s roots will dry properly and help to reduce the root rot which is making the leaves of the lavender yellow.
But root rot can kill lavender plants that have been growing in moist soils for too long. Therefore, it is possible to plant a new lavender plant in the future however it’s worthwhile to try to keep it alive.
- The most frequent causes for the color of lavenders changing is excessive fertilizer in soils, excessive fertilizer, excessive irrigation, poor drainage of the soil or excessive humidity.
- Poor soil drainage is a solution that can be achieved by amending the soil grit or sand to create an amount of at minimum 30% sand to 70 percent soil. This mimics the soil conditions within the Mediterranean range. The lavender plants that are established will require irrigation during times of drought.
- The lavenders have evolved to thrive in soils with low fertility. If the fertility of the soil (particularly nitrogen levels) is excessive, the lavender may become yellow and get less lush, and with less flowers. Reduce the fertility of the soil by adding sand and grit that give the soil the ideal structure but do not add many nutrition to soils, thus neutralizing soils with higher fertility.
- Don’t use fertilizers to your lavender plants. The lavenders that are fertilized are likely to turn yellow and become less attractive and leggy, with less blooms, much as they do in fertile soils.
- The high humidity can cause the color of lavender changing to yellow. To lessen the impact of humidity, you can plant lavender in pots and keep the plants a good space (2-3 inches) away from the other plant species in order to provide better air circulation. A white reflective stone over the lavender will reflect light back on the lavender, helping to keep the plant clean and well-maintained.