Phenomenal lavender typically blooms in the mid-summer and if deadhead regularly, can bloom until the Fall. There are a few reasons why the lavender phenomenal may not bloom…
The most common reasons for lavender phenomenal not blooming are because of fertilizer or planting the lavender in nutrient rich soil. Lavender phenomenal is accustomed to low to medium, sandy soils. Adding fertilizer will result in the lavender producing foliage growth at the expense of blooms.
Consider lavenders of all varieties usually display their best blooms a year after it has been planted as it has had more time to adjust to their new surroundings.
Keep reading for the most common reasons that lavender phenomenal is not blooming and how you can solve the problem…
1. Do not Add fertilizer
The most common reason for lavender phenomenal to not bloom to its full potential is usually because of the use of additional fertilizer or store-bought compost that has been enriched with nutrients.
Lavender phenomenal is a hybrid of English and French lavenders, both of which originate in the South of Europe. In their natural environment, these lavenders grow best in soil that is sandy and reasonably nutrient poor.
The lavender is specifically adapted to these conditions and actually dislikes additional fertilizer. Feeding lavender phenomenal generally results in the plant producing leggy foliage growth with few flowers.
What to do…Avoid feeding the lavender in the future and it may be of benefit to repot the lavender with new soil if it is planted in a pot or container and cut back the leggy growth in the Fall (avoid cutting too close to the woody base).
Lavenders thrive on neglect in terms of soil nutrients and watering.
The best way to encourage the lavender phenomenal to bloom is to attempt to recreate some of the growing conditions of the Mediterranean where lavender thrives such as poor soil, full sun, and infrequent watering.
If the foliage turns yellow then this is another symptom of too much nitrogen for the lavender requirements. If there is no more fertilizer added to the lavender then the plant may recover and produce a stronger bloom the next growing year.
2. Avoid Nutrient Rich Soil
For the same reasons lavender does not require additional fertilizer, lavender also does not like soil that is too rich in nutrients. Nutrient rich soil encourages the foliage to grow and fewer blooms to display.
Lavenders are low-maintenance plants that thrive in low to medium fertility soil as they are accustomed to in their native Southern European range.
Replicating these conditions for your lavender phenomenal is very easy for pots and containers as you have direct control of the soil profile.
The optimal potting mix for phenomenal is simply around 1/3 horticultural sand or grit and 2/3 potting compost. (Read my article to learn about the optimal soil mix for lavenders in pots).
This proportion of sand is similar to the soil of their preferred home range in coastal areas of the Mediterranean.
The sand and grit do not retain nutrients which balances the fertility of the compost to create the low to medium soil profile that lavenders prefer which will encourage the plant to produce more blooms.
Sand and grit also ensure that the soil drains quickly which is essential for lavenders as dry soil is imperative for their root health.
Lavenders in a sunny part of your garden with infrequent watering and sandy soil will produce the strongest aromas from the foliage (because of a higher concentration of oils) and the most flowers.
3. Lavender Phenomenal not in Enough Sun
Perhaps the most important factor for lavender’s phenomenal to display blooms is the amount of direct sunlight.
Lavenders of all varieties prefer full sun. The more sun the lavender receives the stronger the fragrance and the more it blooms.
Lavender do not grow well in partial shade and often displays fewer flowers with more spindly growth.
For Phenomenal planted in pots or containers, move the plant to a place with at least 6 hours of sun per day.
If the lavender is in a raised bed or garden boarder I recommend transplanting it to a pot or area of the garden with more sunshine. Alternatively, you can cut back any overhanging canopy or other plants that might be casting shade on your lavender.
Other possible causes
The amount of sunlight and whether Phenomenal is planted in the appropriate soil are by far the most likely reasons the lavender is not blooming.
However, fewer blooms could be a sign of stress because of other factors…
4. Soil pH
Lavender Phenomenal is a hardy lavender with the characteristics of the resilient English lavender species. However, Phenomenal can tolerate mild soil acidity it prefers soil to be either pH neutral or alkaline (lavender phenomenal grows in soils pH 6.5 to pH 8).
If the lavender has poor spindly growth with not much fragrance, yellow or brown foliage then the lavender may be in soil that is too acidic.
If your garden soil is acidic, it is possible to amend the soil with lime or wood ash to increase the soil pH so that it is alkaline and therefore suitable for lavender growing, but this can take some patience and maintenance as the soil can turn back to its original acidic conditions over time.
(Read my article for more about measuring soil pH and lavenders in acidic soil).
By far the better solution is to transfer the lavender to a pot or container. The pH of the soil in a pot or container is far more easily adjustable with as little as a tablespoon of agricultural lime or half a cup of wood ash (which has an alkaline pH).
5. Heavy Handed Pruning
Lavender phenomenal requires an annual prune to maintain its shape and increase its life span. One of the key benefits of pruning is that it reduces the rate at which the woody base grows.
The woody base of the lavender generally does not support new growth and is more prone to splitting. Lavender will only show its blooms on new growth hence the importance of pruning the lavender to reduce the growth of the woody base.
Prune the lavender once per year either in the Spring or Fall and cut back only the top 1/3 of the flexible lavender growth, avoiding cutting the woody base.
Pruning the lavender to the appropriate amount will stimulate the growth of new stems which support this season’s blooms.
Overwatering
Lavender phenomenal is adapted to dry, breezing conditions with little rainfall.
This adaptable lavender variety can tolerate climates with higher rainfall as long as the soil has been amended with enough sand to increase drainage.
Commercial lavender growers see the most blooms (and more oils) in dry years with relatively few rainy or overcast days.
Overwatering lavender can cause stress to the plant and encourage conditions that increase the chance of the fungal disease root rot.
Lavenders with root rot will have a drooping appearance with brown or yellow foliage. This will also compromise the blooms of the lavender and potentially cause the lavender to die if it is consistently overwatered.
Once Phenomenal has established after its first year, it often does not require watering even during summer. Only if there has been a period without any rain for two weeks should you water your lavender and even then it is a very drought-resistant plant.
(For more information and watering, best practices in different conditions, read my article, how often to water lavender plants).
If your garden soil is slowly draining then I recommend planting lavenders in pots or containers as they have much more favorable drainage conditions and you can easily amend the potting mix with sand to further increase drainage.
This way the roots can remain somewhat dry, which avoids the risk of root rot ensuring a healthy plant with a good bloom in the Summer.
(Read my article to learn about choosing the right pot for lavender).
Key Takeaways:
- Using fertilizer or nutrient rich soil can cause lavender phenomenal to grow foliage at the expense of blooms.
- Sunlight is one of the most important factors for lavender phenomenal to bloom. Grow lavender in full sun for best results.
- Lavender phenomenal will grow in slightly acidic soil (pH 6.5) but prefers to grow in alkaline soils (up to pH 8). Lavender in overly acidic soils can show signs of stress such as not blooming. Replace the soil and add some horticultural lime or wood ash for alkaline soil that is suitable for lavenders.
- Pruning aggressively back to the woody base will limit the amount of new growth that supports flowers. Prune lavender Phenomenal once per, only cutting back the flexible growth.
- Overwatering or slow-draining soils can cause the fungal disease root rot which will result in a lavender that shows signs of stress such as a drooping appearance and a lack of blooms. Ensure that the soil is well draining and amend with horticultural sand or grit if necessary to improve drainage. Establish lavender does not require frequent watering and actually prefers dry conditions similar to their native environment in coastal Southern Europe.