French lavender - help!

[ZeeR82]

Hoping for some guidance and pointers for French lavender please.

I planted this little bush in 2022 and at the time of planting two years ago, the flower bulbs were vibrant purple. However, now the bush looks healthy and the flower bulbs are in full bloom but as you will see in the image, the coverage of the colour is partial and it's been like that for nearly 12 weeks now!

The plant is well watered and in full sun - our garden is south facing. Last year it was the same, and I thought that over time the colour would fully develop by summer - but it never did and it seems it will be the same this year! Somehow, I don't have this problem with my English lavender plants in the same soil and flower bed.

In the garden centres, all of the French lavender bushes are in full colour. I'm a little reluctant to add plant feed in case it suddenly becomes unmanageable size wise.

What am I missing? Any recommendations?

Hello ZeeR82

Your French lavender is naturally doing what it is supposed to do i.e. the small purple flowers to the sides of the flower heads are coming our a few at a time.

What has occurred prior to you purchasing the French lavender is that the grower a number of weeks before being supplied to the garden centre will have given them a treatment of either gibberellic acid or ethylene to induce all of the small purple to come out at once thus creating more of an impact i.e. the appearance of a purple head.

Unfortunately there is nothing you can buy to apply to your French lavender to induce all of the small purple flowers to come out all at once.

In relation to giving any nutrients to your French lavender little feeding is required although you could sprinkle a very small amount of potash around the base of your plant to increase flowering. However the purple flowers are so small it would be difficult to see any real difference.

Don‘t add manure or high nitrogen fertiliser as your French lavender will grow larger and will have a tendency to flop.

Cut back the long flower stalks once they have finished flowering in September/October with a clean and sharp pair of sheers.

Happy gardening
TheSustainableGardener

Ah that makes sense that they would enhance the flowers using "supplements". I'll give the potash a go. Thank you.