Petal of the Rose of Trinsic
When eaten by a character, a petal bestows +5 Strength for a duration of 5 minutes. This buff is in addition to other buffs to Strength, such as Potions of strength, Bless, and equipment strength bonuses. You cannot consume another petal until the 5 minute duration has expired. You can then eat another one immediately, providing an 'almost' uninterrupted effect.
If the buff did not stack with the stronger Strength buffs from potions etc. the petals would be almost useless since their effect is inferior. But since the buff does stack, the petals are useful to provide a small boost to hit points, damage, and carrying capacity.