That sounds reasonable. Revising...
Blood-Draining Leaves (Ex): A singing tree has a number of leaves equal to its normal maximum hit point total. Each round, it may release a number of individual leaves equal to its Hit Dice and send them to attack prey. The leaves are treated as separate creatures, but use the singing tree's base attack and base saving throw bonuses. Damage dealt to the leaves has no effect on the singing tree, nor do effects that target the leaves, and vice versa. While attached to the singing tree, the leaves are not considered separate creatures and cannot be targeted individually.
Singing Tree Leaf
Diminutive Plant
Hit Dice: 1/4d8 (1 hp)
Initiative: +4
Speed: Fly 30 ft. (poor)
Armor Class: 18 (+4 size, +4 Dex), touch 18, flat-footed 14
Base Attack/Grapple: +8/+3 (+15 when attached)
Attack: Feeding-tube +16 melee (1 plus attach)
Full Attack: Feeding-tube +16 melee (1 plus attach)
Space/Reach: 1 ft./0 ft.
Special Attacks: Attach, blood drain
Special Qualities: Low-light vision
Saves: Fort +8, Ref +8, Will +4
Abilities: Str 1, Dex 19, Con 10, Int -, Wis 11, Cha 1
Skills: -
Feats: Hover (B), Weapon Finesse
Attach (Ex): If a singing tree leaf hits with a feeding tube attack, it latches onto the opponent’s body. An attached leaf is effectively grappling its prey. The leaf loses its Dexterity bonus to AC and has an AC of 14, but holds on with great tenacity. Leaves have a +12 racial bonus on grapple checks (already figured into the Base Attack/Grapple entry above).
An attached singing tree leaf can be struck with a weapon or grappled itself. To remove an attached singing tree leaf through grappling, the opponent must achieve a pin against the leaf.
Blood Drain (Ex): A singing tree's leaves drains blood, dealing 1 point of Constitution damage in any round when it begins its turn attached to a victim. Once it has dealt 1 point of Constitution damage, it detaches and returns to the singing tree.
Part of a Greater Whole (Ex): Since the singing tree leaves are extensions of the singing tree itself, the leaves use the base attack bonus and base saving throw bonuses of the singing tree.