It is a semelparous species, putting all its reproductive effort into producing single large inflorescence up to 3 metres (10 ft) tall, and then dying.

[1] Inflorescences of L. telekii also possesses a large pith-volume for internal water storage and marcescent foliage which could provide insulation.

[1] Each flower is subtended by a long hairy bract, and the overall appearance has led to the nickname "Cousin Itt lobelia".

It inhabits the drier hill slopes, while its close relative Lobelia keniensis prefers the moister valley bottoms.

The hill slopes often have rocky moraines that are home to Mount Kenya rock hyrax, which sometimes eat lobelia leaves and inflorescences,[7] but herbivores are generally deterred by the lobelia's bitter toxic sap, which contains alkaloids, probably including lobeline.Lobelia telekii was previously classified under the Rhynchopetalum section within the Tupa subgenus.