Onosma are hardy perennials that range from 15 to 45 cm (6 to 18 inches) in height.
Onosma plants bloom in the summer. They carry tubular flowers of pink, yellow, or white that are surrounded by green calyxes.
Some common names of this popular rock garden plant include Golden Drop and Golden-flowered Onosma.
Onosma alborosea photograph by wlcutler.
Onosma javorkae picture by elisabetta2005.
When growing Golden drop outdoors from seeds they should be sown in the autumn. Once sown lightly cover the golden drop seeds.
Onosma genus plants like to grow in sunny conditions and have a preference for a gritty, dry and poor soil.
Indoors it is best to start growing Golden drop and other Onosma about three months before they are due to be planted out after the last frost of spring.
It takes from one to two months for Golden drops to germinate at 10 degrees Centigrade (50°F).
Once ready transplant, Onosma species into the garden with a spacing of 15 cm (6 inches; small) to 45 cm (18 inches; large varieties).
In the spring it is best to add manure to the soil around Golden drop. Mulching with rock chippings can help to keep the roots cool.
Unfortunately, Onosma are susceptible to rotting in the winter, so it is best to mulch a second time, but with organic matter.
Although perennials, Onosma are short lived. More plants should be propagated to replace them every few years. This can be achieved by taking cuttings of golden drop in the summertime.
The Onosma genus is quite diverse, featuring around 80 species. These perennials are known for their bright yellow or white tubular flowers.
Onosma plants can add interest to gardens, especially rock gardens or xeriscape designs, thanks to their drought-tolerant nature and unique blossoms.
Onosma tauricum is often grown for its brilliant yellow flowers that add a pop of color to dry, rocky landscapes.
Onosma plants aren't typically grown for their fragrance. They're more appreciated for their resilience in dry conditions and distinctive flowers.
Onosma thrives in sunny locations with well-drained soil. Being drought-tolerant, they are well-suited for rock gardens or areas with low rainfall.
Onosma is not currently listed as invasive in the USA. Always check with local regulations as conditions can change over time.
If you need to remove Onosma, carefully dig up the plants, ensuring you get all of the root system to prevent regrowth.
Onosma, a member of the Boraginaceae family, is a group of perennial herbs typically found in mountainous regions. They are often recognized for their long, tubular flowers that hang in clusters.
For best growth, plant Onosma in a sunny spot with well-drained soil. These plants prefer cooler, mountain-like conditions, making them ideal for rock gardens or alpine houses. Planting is usually carried out in spring or autumn, ensuring a lovely display of blooms during the growing season.