The invasive Prunus tree species have showy and fragrant white flowers, seen in this undated photo. (Courtesy/Alaska Department of Natural Resources)

State officials have barred the import, transport and sale of two fast-growing invasive species that were once popular garden ornamentals but have now wreaked havoc on natural vegetation.

The Alaska Division of Agriculture on Friday said it issued a quarantine for the two species: Prunus padus, commonly known as the European bird cherry…