Typha laxmanni, the graceful cattail will not produce catkins.
I grow the above cattail in above ground containers. They are very hardy and produce great foliage every year. But they have not flowered in about 6-8 years. Literature says that it may not produce seed heads in warmer climates (zone 9-10). My home is in zone 7 and 900 ft above sea level and surrounded by woods, so I wouldn't consider that to be a tropical setting. Any suggestions regarding nutrition or culture would be appreciated. Thanks
Baltimore County Maryland
While we do not have specific culture information for this species, perhaps the soil in the containers is warming enough to the point that it is causing the plants not to flower. Container media does heat up (and cool down) more rapidly and more drastically than soil in the ground.
The main suspect for plants reluctant to bloom is insufficient sunlight, as they are adapted to growing in open wet areas with high light levels. Are these planters receiving at least 6-8 hours of direct sun a day in the summer?
Have you ever fertilized them? Container soil can become depleted of some nutrients over time and may benefit from a general-purpose fertilizer one or more applications per year (depending on the formulation). Fertilizer won't support flowering if the sun levels are insufficient, but barring that, it may be a reason.
There is a mention on the USDA Forest Service page for a related species (one of our native Typha) that unsubmerged plants have been observed not flowering. Perhaps this one needs to have a few inches of water over its roots at all times to thrive and begin to bloom.