11 Reasons Your Lavender Isn’t Blooming and How to Fix it
If your lavender is struggling to bloom this season, there are a few common issues that can contribute to the problem. So, what should you do about it? In this article, gardening expert and former organic lavender farmer Logan Hailey examines the most common reasons that lavender fails to bloom, and how to fix it!
Alluring purple blossoms and sweet perfume of lavender make it one of the most popular garden herbs on the planet. But what’s the point of growing this popular herb if it isn’t producing flowers?
While lavender leaves have a mild camphor or rosemary scent, it is the vibrant spike flowers that are most cherished in the garden. If your lavender isn’t blooming, it could be a sign that something is wrong with the soil or the plant that is preventing it from sending up blooms.
So why does it happen? What causes these herbaceous perennials to stop their famed purple blooms in their tracks? Let’s dig into the most likely reasons your lavender isn’t flowering and how to fix it!
Too Much Nitrogen
When it comes to fertility, lavender is almost the opposite of most garden plants. This perennial herb actually thrives without added fertilizer. Too much fertilizer can be detrimental to the plant’s flowering cycle.
In particular, too much nitrogen promotes an excessive amount of foliage growth. The result is leggy, elongated stem growth with an abundance of leaves and little to no flowers.
Lavender is native to the Mediterranean where it grows wild on gravelly exposed slopes with very little soil fertility. This adaptation has led the plant to prefer nutrient-poor soil that is gravelly or sandy in nature.
The loamy, fertile soils of some gardens can actually send the plant into leaf growth “overdrive” and prevent it from blooming. If it does send up flowers, they are often low-fragrance due to too much nitrate availability. A flush of synthetic nitrogen can even cause weakened stems, infestations of sap-sucking pests like aphids, or death of the plant.
How to Fix It
We recommend not adding any fertilizer to your lavender beds at all. Avoid synthetic fertilizers and manure at all costs. If you recently transplanted lavender or are growing it in a pot, the only form of nutrients it should receive is a little bit of aged compost with low nitrate content.
If you already fertilized, you will need to adjust the ratio of nitrogen to potassium and other minerals to promote flowering. You can do this by mixing in a small amount of bone meal, blood meal, or kelp into the soil at the base.
You can also dilute the fertility by adding sand or peat moss into the soil. Focus on the perimeter of the root zone and be sure you don’t disrupt the root ball.
The Plant is Too Young
Some gardeners panic about the absence of flowers without realizing that their plants are just too young to bloom. Just like humans, lavender has to reach a mature phase before it can reproduce. If newly planted from cuttings or even from seeds, it has to get firmly rooted and established in its new home.
Most varieties take 1 to 3 years to fully mature. Yes, many varieties can bloom in the first year. However, this initial flowering may not be as abundant as the second and third-year displays.
How to Fix It
Patience is a virtue! Check your calendar to see when you planted. Depending on your climate, spring is usually the best time to transplant seedlings and they may send up some flowers by summer.
Not Enough Sunlight
Lavender’s Mediterranean home is known for the heat and bright sunshine. All plants need sunshine to photosynthesize, but this shrub is especially picky about its light requirements. It does not tolerate shade and will throw a fit when it doesn’t get at least 6-8 hours of direct sunshine per day.
Other symptoms of plants without enough light include:
- Pale, yellowing, or brown leaves
- Stunted, slow growth
- No flowers
- Less fragrance (low essential oil content)
- More susceptibility to root rot
If your lavender is being shaded out by buildings, garden structures, trees, or larger shrubs, it probably won’t flower. If it does try to flower in the shade, the blooms tend to be small and lacking in fragrance. There is no way to bypass this plant’s sun-craving nature. Partial shade unfortunately isn’t an option.
How to Fix It
Always plant in the most open, exposed part of your garden. Observe how the sun moves over your garden throughout the day and be sure that it isn’t getting too much shade in the morning or evenings.
Cloudy or rainy days are fine as long as the plant still has open exposure to the sky. You may need to prune surrounding plants or dig up the plant and transplant it to a different location.
If growing in a container, move the plant to the sunniest outdoor areas as the seasons change. If growing indoors, be sure that it is by the brightest south-facing window or add supplementary artificial lighting. Rotate the pot every week or so to encourage even growth on all sides.
Too Much Water
Thanks to its robust drought tolerance, this hardy shrub is popular in dry areas like the U.S. southwest. Too much water can do more harm than good.
This perennial herb has evolved to withstand long periods without water. In fact, it actually enjoys dry soils and, once established, it can get by without any irrigation at all. Overwatering predisposes the plant to a range of diseases and problems, including:
The most common reason for dying lavender is rotten roots caused by overwatering and soggy soils. A rotten, stinky odor may come from the root zone.
Similar to root rot, this fungus-like disease will attack the woody base of the plant during the wet season. Browning or yellowing foliage typically appears at the base of the plant first, then movies upward. The bark may also look blackened or like it’s been stained with cinnamon.
Droopy, wilted foliage
When the soil is very wet but your plant is wilted, it’s a sure sign that the roots are unhappy.
Overwatering can cause issues, which includes bringing up mineral nutrients to the leaves, which leads to stressed or yellowing foliage.
Too much water can significantly slow growth because the roots are suffocated by their soggy environment.
Don’t get it wrong— lavender does need some water, especially when it is in the juvenile establishment phase. But too much moisture can wreak havoc on your Mediterranean herb garden.
How to Fix It
Once you notice signs of overwatering, cut back on irrigation and allow the soil to dry out at least 6” deep. Do not water again until a finger stuck in the soil comes out dry. Then, only water after long periods without rain. Many commercial lavender farms only irrigate mature plants once or twice a year during the peak summer heat.
If you are growing in an excessively rainy climate like the U.S. northeast, southeast, or northwest, you may need to dig it up and move to a better drained location. Use the tips below to improve soil drainage and consider planting in raised mounds or pots.
Poor Soil Drainage
More than anything else, lavender hates to have “wet feet”. If your roots are sitting in soggy or waterlogged soil, there is no way it will send up flowers.
Drainage is the key to healthy plants because it allows the root zone to stay aerated and breathable, resulting in vigorous above-ground growth and energy to put into blooming.
Lavender’s native soils are known for their extremely quick drainage. The rocky, gravelly, and sandy texture allows water to move through the soil profile very quickly. In your garden, lavender should never be planted in heavy clay soils where water can pool up or sit around.
Poor soil drainage predisposes this herb to all of the issues described above. Moreover, overwatering combined with poor soil drainage are a recipe for disaster!
How to Fix It
Avoid planting in dense or heavy soils with high clay content. Instead, generously amend your soil with:
- Horticultural sand
- Peat moss
- Oyster shells
A broadfork is also an incredible tool. You can even use it to improve the drainage around existing plants without moving them! Simply dig the tool deep in the soil about 6-8” from the base of the plant.
Gently lift the forks upward (without uprooting the plant) to bring aeration into the lower layers. Then add one or more of the amendments listed above.
If your garden’s native soil is high in clay, consider growing in mounds above the soil surface so that water can drain more quickly. You can do this by layering sand, limestone, pea gravel, and/or hardwood bark about 12-24” above the ground.
Pruning is essential for healthy plant growth, but over-pruning the plant can cause unnecessary stress that leads to reduced flowering. Cutting back large portions of stems and leaves reduces the plant’s ability to photosynthesize.
As a result, it will end up stressed and without sufficient energy to fuel new blooms. If you cut into the hardwood of the crown, it can also cause it to go into survival mode.
How to Fix It
Ideally, you should be pruning twice per year— once in the spring after the first flush of flowers and again in the fall after the last flowers have started to fade. If you pruned it too hard last autumn, there may be less new growth this spring.
You will have to give the plant time to regenerate and avoid cutting off any more foliage. In the future, only cut back about ½ to ⅔ of the plant and always leave a couple inches of soft, green growth near the base.
Woody Growth (Not Enough Pruning)
While over-pruning can be an issue, under-pruning is equally problematic. Proper pruning actually encourages additional flower production. It promotes vigorous growth and ensures that the plant regularly sends up lush new shoots.
If you’ve never pruned your lavender, the plant can become tall, unshapely, leggy, and more prone to collapsing.
Without pruning, it will start developing a lot of woody growth at the base. This hardwood won’t produce floral stems. The plant will keep putting energy into this wooden “trunk” instead of channeling its efforts toward the green, herbaceous growth that fuels flower production.
How to Fix It
Woody plants can be rescued by restarting your pruning routine. Begin by cutting back up to ⅔ of the plant in the fall. Strategically remove a few woody or congested stems at a time, but don’t cut off all the hard portions at once.
It may take a few seasons to properly regenerate the plant by slowly removing woody portions. Focus on re-establishing a mounded shape and leaving 2-3” of soft green growth near the base.
In the spring, you should see signs of young new shoots from the lower, woody stems. If there are no other problems with the plant, these new shoots are likely to send up flowers. Continue with spring and fall pruning for the entire lifespan of your plant.
Sudden Cold Snap
While English and hybrid lavenders are hardy to grow in zone 5, they typically only withstand the extreme cold during their dormant phase. If your plant broke out of dormancy during a premature spring warming period, it probably started sprouting and potentially sending up flower stalks.
In the event of a sudden cold snap, this tender new growth can quickly get damaged. You may notice gray or blackened portions of the plant.
How to Fix It
Prune away the frost-damaged areas and preserve any new growth that has been saved. You may want to mulch around the base of the plants with more gravel or bark for a little insulation. Wait for warmer weather and hope that your lavender has enough root strength to send up new shoots.
There are 40 different species of Lavandula and over 450 varieties of this infamous herb. If a cultivar is not suited to your garden’s soil, temperatures, rainfall, and humidity, it may not flower at all.
For example, a cold-hardy English lavender like ‘Munstead’ will be very stressed out and prone to disease in the ultra-humid heat of Florida. Similarly, a Spanish lavender like ‘Kew Red’ is unlikely to flower (or even survive) in a climate like Colorado unless it is kept in a container and brought indoors for the winter.
While lavender is native to the Mediterranean, you can certainly grow it in areas that are far different from a Mediterranean climate. However you may need to make some changes to your growing methods to ensure it thrives.
Modern breeding efforts have developed varieties that can be grown almost anywhere in zones 4 through 11. The key is to source from local plant nurseries and check with regional garden resources to find what works best for your climate.
How to Fix It
Be sure to choose a variety that has been specifically bred for your region. If you live in the south, you should probably go with Spanish lavenders (Lavandula stoechas). For cold northern gardens, you may choose English lavender (Lavandula angustifolia) or Lavandin hybrids (Lavandula intermedia).
Wrong Soil pH
Lavender loves neutral to slightly alkaline, calcareous soil. This means it should be rich in calcium and a pH between 6.5 and 7.5. If the soil is too acidic (below 6.5), it can’t properly absorb the rocky trace minerals it needs to thrive.
How to Fix It
Herb gardeners with acidic soil should add dolomitic lime, limestone gravel, or baking soda to alkalize the ground. Clay soils are particularly prone to being too acidic (and poorly drained) for lavender’s liking.
If you have clay soils, avoid incorporating peat moss or bark into your beds. Never mulch with sawdust or pine needles, as these are especially acidic.
It’s Not the Right Season
Each type of lavender has a different bloom cycle and seasonality. You cannot expect Lavandin hybrids like ‘Provence’ to start blooming at the first sign of spring. Similarly, English lavenders may not bloom all the way into the fall the way that Spanish varieties do.
How to Fix It
Check what species you’ve planted, the age of the plant, and the current time of season. Spanish and French lavenders tend to bloom first in the spring and continue with 2-3 flushes of flowers throughout the summer and fall.
English lavenders are more likely to yield one big, longstanding flush of blossoms in the mid-summer. Lavandin hybrids usually bloom from mid-summer into the autumn.
Nobody is growing lavender just for the foliage. If you are yearning for those decadent purple flowers, ensure that your plant has:
- Low fertility (no fertilizer).
- 6-8 hours of direct sunlight (no shade).
- Well-drained soil that isn’t too acidic.
- At least 1 year to establish.
- Soil that dries out between waterings.
- Twice annual pruning.
- The proper variety for your climate.
Once established, lavender is a laid back herb that doesn’t require much maintenance. However, it can be difficult to understand its preferences as a beginner.