According to observations of naturalists and beekeepers.
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Hyssop is a perennial plant that is native to the Mediterranean region and has been imported and naturalized in the US and Canada. It grows along roadsides and is sometimes found as a garden herb. Hyssop is quite similar in appearance to other members of the mint family. Its volatile oil possesses a highly aromatic camphor-like smell.
It should be noted that there are a number of other common plants found in North America that go by a variation of the name "hyssop." These include giant hyssop (Agastache sp.), hedge hyssop (Gratiola officinalis), and water hyssop (Bacopa sp.). None of these plants are members of the genus Hyssopus.
This plant is present in at least 17 states/provinces in this country.
Hyssop is a brightly colored shrub or subshrub that ranges from 30 to 60 cm (12 to 24 in) in height. The stem is woody at the base, from which grows a number of upright branches. Its leaves are lanceolate, dark green, and from 2 to 2.5 cm (0.79 to 0.98 in) long.
During the summer, hyssop produces pink, blue, or, more rarely, white fragrant flowers. These give rise to small oblong achenes.
The plant blooms from July to September. The fruits ripen in August.
The plant is commonly used by beekeepers to produce nectar from which Western Honey Bees make a rich and aromatic honey.
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Salix nigra (aka: Black willow, Swamp willow, Southwestern black willow, Gulf black willow, Scythe-leaved willow)
Cercis canadensis (aka: Eastern redbud, Redbud, Cersis Reniformis)
Malus angustifolia (aka: American crab apple, Buncombe crab apple, Crabtree, Narrowleaf crab, Narrowleaf crab apple, Southern crab, Southern crab apple)
Aronia arbutifolia (aka: Red chokeberry)
Ulmus americana (aka: American elm, White elm, Water elm, Soft elm, Florida elm)
Prunus americana (aka: American plum, Goose plum, River plum, Wild plum)
Salix discolor (aka: Pussy willow, American pussy willow, Glaucous willow, Large pussy willow)
Pyrus communis (aka: European pear, Common pear)
Celtis laevigata (aka: Hackberry, Sugarberry, Lowland hackberry, Sugar hackberry, Arizona sugarberry, Netleaf hackberry, Small's hackberry, Southern hackberry, Texas sugarberry)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Vaccinium corymbosum (aka: Highbush blueberry, High-bush blueberry, Northern highbush blueberry, Tall blueberry, Rabbiteye blueberry, Blue huckleberry, Tall huckleberry, Swamp huckleberry, High blueberry, Swamp blueberry)
Malus domestica (aka: Pyrus pumila, Malus pumila, Apple)
Prunus cerasus (aka: Sour cherry, Tart cherry, Dwarf cherry, Montmorency cherry)
Malus coronaria (aka: Sweet crab apple, Garland crab, Alabama crab, Allegheny crab, American crab, Baltimore crab apple, Buncombe crab, Dawson crab, Dunbar crab, Fragrant crab, Garland tree, Lanceleaf crab apple, Missouri crab, Sweet-scented crab, Sweet wild crab, Wild crab, Wild sweet crab, Wild Crab Apple)
Populus tremuloides (aka: Quaking aspen, Trembling aspen, Aspen, American aspen, Mountain aspen, Golden aspen, Trembling poplar, White poplar, Popple, Alamo Blanco)
Liriodendron tulipifera (aka: Tuliptree, Blue-poplar, Tulip-poplar, Yellow-poplar, Yellow wood)
Acer saccharum (aka: Sugar maple, Rock maple, Hard maple)
Celtis occidentalis (aka: Common hackberry, Bastard elm, Nettle-tree, Northern hackberry)
Ilex opaca (aka: American holly, Dune holly, Hummock holly, Scrub holly)
Acer platanoides (aka: Norway maple)