| Heliotropium, Boraginaceae, Embryophyte, Lobelia erinus, Ageratum houstonianum|
The garden heliotrope (Heliotropium arborescens) is a highly fragrant perennial plant, originally from Peru. It is especially notable for its intense, rather vanilla-like fragrance. Common names include cherry pie and common heliotrope. Note that the common name "garden heliotrope" may also refer to Valerian (herb), which is not a heliotropium variety.
The seeds are poisonous. The ASPCA's Animal Poison Control Center article on heliotropes lists them as a substance which is toxic to horses and can induce liver failure in equines. The plant is not very palatable, but will be eaten by animals with no other forage; poisonings typically occur from ingestion of green plant material or material in hay. The toxic components can cause liver failure, referred to as "walking disease" or "sleepy staggers". Signs include weight loss, weakness, sleepiness, yawning, incoordination, yellowish discoloration to mucous membranes (icterus), neurologic problems secondary to liver failure (aimless walking, chewing motions, head pressing). Animals may appear to be normal at first, then become suddenly affected; the syndrome progresses rapidly over a few days to a week.
As a perennial, is hardy in zones 9 to 11, and requires wintering indoors in zones 8 or colder. It can also be grown as an annual in those areas.
During the Victorian era in England this plant gained great recognition, often appearing in gardens and the herbaceous borders of parks. They were also grown as standards. Its popularity may have become less in more modern times, but hardy and colourful varieties, such as 'Princess Marina', have ensured that this plant still regularly appears in seed catalogues and garden centres. Other popular varieties include, 'Mary Fox', the highly scented 'White Lady' or 'White Queen' and a taller variety 'Florence Nightingale'. A vanilla-scented heliotrope was laid on the coffin of Emily Dickinson.'Fragrant delight' has more fragrant purple flowers, and leaves with purple highlights.
'Marine' has large highly fragrant dark purple flowerheads to 15 cm (6 in) diameter, and burgundy leaves.
'Sweet heaven' has paler fragrant flowers and is more heat-tolerant.
'White' has flowers that smell of almonds.
Heliotropium arborescens Wikipedia