Sprinkle blood meal over them. That works pretty well for me.
Those tree rats are maddening, really!

Rebaru,

We use blood meal also. Milorganite is another product that helps.
The best repellants have been Fox urine, available in small bottles and other similar nasty smelling concoctions.

One botanical garden used a gross spray of road kill in a dedicated blender. It was extremely effective.

A crocus that, for me, has been immune to animal predations is Crocus tommasinianus and its several varieties.
It might help to co-mingle the goodies with poisonous things like Galanthus nivalis, small Narcissus and Erianthus. It's a matter of trial and error on such things.

Now if I can just find a Beaver repellant for the Red Maples.

Mike519

Mike519 - what a lot of suggestions! the blood meal will be easiest to lay my hands on first. the hardest.... not sure! i wish i could help you with the beavers! thanks!