A Different Approach to Growing Basil by Amy Norwood

 

Photo: Amy Norwood

Basil is a wonderful herb for the summer garden because it pairs so well with tomatoes and other summer garden veggies!  Left to its own devices, the basil plant will produce a spike of small flowers on the end of each stem.  The flowers eventually become seeds.  The conventional wisdom for growing basil is to pinch off the flower spikes when they appear.  If you want to eat the basil, by pinching the flowers you encourage the plant to put its energy into growing leaves, not making seeds.

Sterile basil is the exception to this rule.  The flowers of sterile basil varieties don’t go to seed.  So, in theory, you can keep the basil flowers without affecting the plant’s leaf production.

In searching online, I’ve found two sterile basil varieties (there may be others I missed.)  One is a generic variety called African Blue Basil.  The other is a commercial cultivar called Amazel Basil.  I usually see Amazel Basil for sale in the spring at various Jefferson County garden centers.  I haven’t seen African Blue, but I wasn’t looking for it particularly, either.

I’ve grown Amazel Basil for several seasons now.  Until last season I dutifully pinched off the flowers, really just because that’s what I had always done.  Last season, due to business and laziness, I let the flowers stay all season.  This is what I learned from the experience.

First, I thought the production and taste of the basil leaves was the same for flowered and flower-free Amazel Basil.  But that assessment is based on my memory of past seasons when I pinched the flowers.  A more formal trial situation, where plants are grown side by side and half are pinched and the other half not, would give the most definitive answer to this question.

Second, bees love basil flowers!  If you want to feed the bees while you feed yourself, leaving the flowers on your sterile basil plant might be a good option.  Last season, so many types of bees visited my plants that I felt I had a bee laboratory.  I really enjoyed watching them going about their business on the flowers.

Third, by the end of the season, the flower spikes were huge, a foot or more in length.  Overall the plants were probably twice as big as they would have been with pinched flowers.  The problem with this was water consumption.  I grow basil in pots to minimize earwig damage to the leaves (I’ve found growing in pots to be very effective for this purpose.)  But plants grown in pots dry out more quickly than plants grown in the ground.  By the end of our hot summer, I was watering my giant basil plants twice a day to keep them from drooping.  That got old pretty quickly.  I considered cutting off the flowers, but I didn’t want to upset the bees, so I didn’t.  I kept watering.

Finally, I learned that Japanese beetles like basil flowers better than the leaves!  Every morning during Japanese beetle season I inspected my basil plants for beetles (basil is one of their favorite meals.)  Every morning I found beetles in the flowers and dispatched them on the spot.  I never found them on leaves and saw no leaf damage.  The usual remedy for Japanese beetles on basil plants is to cover the plants with fine netting.  That’s not so difficult to do, but I did appreciate not having to do it last season.

Photo: Amy Norwood

So, armed with this knowledge, how will I grow basil this season?  My plan is this – grow Amazel Basil and leave one or two flower spikes on each plant.  My hope is that the flower spikes will work as a trap crop for the Japanese beetles while the plants need less water.  As for the bees, they have other places to forage in my yard. 

https://planttalk.colostate.edu/topics/annuals-perennials/1055-basil/

https://plants.ces.ncsu.edu/plants/ocimum-kilimandscharicum-x-basilicum/#:~:text=African%20Blue%20Basil%20is%20a,plant%20growing%20like%20other%20basils