Tagetes.
Perhaps a Tulip?
Tea roses, tiger lily, trumpet vine, tulip and turtlehead are flowers. They begin with the letter t.
tulip Tigerlily Tuberose
tulip Tulip, Tuberose, Trumpet Flower
Elizabeth T Billington has written: 'Adventure with flowers' -- subject(s): Flowers
IrisImpatiensIpomoeaIxia
Terrisa Flowers goes by T Joi.
If you mean "U", there are 0 flowers that start with "U".
orchid
Runuculus
Aspidistra.
rose