Spray bottle: Is sprayed directly on plant foliage. A premixed solution with anticoagulant included, easy to bust out quickly. Has a decent shelf life, run water through spritzer after each use to prevent clogging. Red/brown spray temporarily discolors leaves. Lasts well on foliage it is applied to, but should be applied every few weeks to protect new growth. Best used on a smaller number of easily accessed plants.
Granular: Is sprinkled on the ground throughout planting. Activated by water, so water after application or apply before rain. Can be applied as a border but efficacy is reduced. Repels rabbits well but may not repel deer from taller plants. Tidy as there is no water involved, and is generally the best choice for suburban applications where rabbits are the main problem. One application lasts three months. Long shelf life if kept dry.
Powder: A dry concentrate of the spray bottle form. Mixed into a solution and sprayed on foliage, generally with a pump sprayer. Best choice for larger/taller plantings that need protection from deer. Lasts well on foliage it is applied to, but should be applied every few weeks to protect new growth. Once mixed, batches have a short shelf life so should be applied all at once. Powder has an excellent shelf life if kept dry. Spray temporarily discolors leaves.