I know they draw to it. would it help swarming. any other ideas.
Welcome Stung, Yes they are drawn to it. (Lemongrass oil) I am told if you put it in a swarm catch box it may help draw a swarm.
I have found the best attractant to a swarm from my experience is a seasoned nuc box with at least one frame of comb and the other frames with foundation. The foundation is to help assure no cross comb in case you do not reach the swarm box in time. The bees start drawing new comb very soon after arriving in their new home.
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My mom has some lemongrass in her garden. The bees don't seem to really notice it. The essential oil is generally what's used for swarm lures, but I'm not sure that the plant just as it is attracts them very much. Mom's is still small though, so maybe they'll investigate it more when it's larger.
I doubt that bees will be drawn by lemongrass plants nearby. It is the internal sap of the leaves infused into oil that is potent and effective.
I take a Qtip, dip it into some good quality lemongrass oil. Dab at the box entrance, mark the top of one of the frames, place the Qtip in a small zip lock bag and put it into the bottom of your swarm box.
And as Ben Framed said, a previously used box or frames gives it an irresistible bee smell they like.
What Bob said x2.
Jim Altmiller
I was a little late this year setting up a swarm box so maybe that is why it didn't work. However bees swarm all year long down here.
Up until the rain came they were nailing this Agave every day.
https://photos.app.goo.gl/hFe1ivFrVuB1HJVH9
The bees aren't interested in my lemongrass plants but seem to love the oil we use in the swarm traps.