Sky Painting with Pollen

New century plant hybrids don’t usually just happen. Yes, a bee can occasionally transfer pollen, resulting in a new hybrid, but as a rule, new hybrids require an incredible amount of work, spearheaded here by our volunteer, Vince Schneider. Vince coordinates pollen collection, storage, as well as the pollination process. While we love agaves with tall spikes, these provide a unique set of challenges to extract pollen as well as to climb high enough to make crosses, while keeping the incredible swarms of honeybees at bay. Our flowering Agave ‘Green Goblet’ was this years challenge as the flower spike reached 25′ tall.

We first prepare a spreadsheet with the agaves that will flower the current year, with spike emergence dates and projected flower opening dates, which are usually 7-8 weeks after the spikes first emerge. The next step is to plan out our crosses for the year. We made our first agave crosses in 2009, so we’ve got a bit of a track record now to work from. We try to envision what cross would result in a unique and desirable offspring. Occasionally, we are surprised, but in most cases the offspring are pretty close to what we envisioned. When possible, we try to create offspring with minimal offsetting, since too much offsetting can be difficult to manage in many small garden spaces.

We are fortunate that agave pollen stores well. We gather all the pollen possible, which is subsequently cleaned and frozen for use in future years, or shared for the Mangave breeding program of Hans Hansen at Walters Gardens. Despite our best efforts, not all of our 50 crosses we make each year set seed. Some agave parents just aren’t conjugally wired to mate, while others may fail to set seed if the daytime temperatures are too high. We’ve also learned through the years, that the best seeds set on the upper 1/3 of the flower panicles. For some reason, the lower flower clusters rarely set well. We typically make the same cross up to 50 different times per flower panicle, and then may duplicate those efforts again on a higher flower cluster. All crosses are tagged with breeding tags, which allow us to later harvest and label the successful crosses.

This year, we were fortunate to have one of our clumps of Agave ovatifolia ‘Vanzie’ flower with an abnormally short flower spike less that 12′ in height. This made crossing substantially easier to which Vince will attest.

Join us during our upcoming Summer Open Nursery & Garden Days, July 12-14 & 19-21, 2024 to see the agaves flowering in the garden and see what all the buzz is about.