Pictures shown are mature trees for sake of reference. Semi-dwarf size when full grown.
This product is sold as a large, bareroot 5-6 foot tall tree.
(Not full grown)
 
Zestar!®
Early Season
Fruit
Fruit size: 3-inch average (7.6 cm)
Fruit color: 60 to 85% red
Flavor: Most outstanding feature! Excellent sweet-tart balance with a brown sugar overtone
Texture: Light, crisp and juicy
Storage life: 2 months
Culinary use: Excellent for fresh eating and cooking
 
Disease resistance
Scab: Susceptible Fire blight: Moderate resistance
Tree
Region: Grows best in northern U.S., Canada and areas with relatively cooler climate Hardiness zones: 4b, 4a, 3b, USDA Plant Hardiness Zone map Growth habit: Upright to spreading Vigor: High in early years, but attains a spur-type habit and moderate vigor as it matures Precocity: Good on dwarf rootstocks Bloom: Very early Ripening season: EarlyFruit adherence: Good. Usually harvested in 2 pickings.
 
Excerpted from and for more information see the following link: University of MN - Zestar!