Digitalis obscura (Sunset Foxglove) is a shrubby perennial boasting lovely racemes of nodding, rust-brown to yellow or orange-yellow flowers with red veins within. Blooming from late spring to midsummer, they rise atop leafy stems clad with lance-shaped to linear, gray-green, willow-like leaves.
I. Appearance and Characteristics
Digitalis obscura, commonly called willow-leaved foxglove or dusty foxglove or Spanish rusty foxglove, is a woody perennial plant belonging to the family Plantaginaceae.
Digitalis obscura is native to the western Mediterranean in eastern and southern Spain and northern Morocco, where it is found growing in dry, open woods and often on limestone.
Digitalis obscura subsp. laciniata is found in the mountains of southern Spain and northern Morocco. It has serrate or deeply toothed leaf margins in contrast to the smooth margins of the species.
Digitalis obscura is a shrub or herbaceous perennial growing from a woody base, reaching 1 to 3.9 feet (0.30 to 1.19 m) tall. The stems are smooth and erect. The long leaves are basal and form in a rosette fashion growing outward closer to the ground. Smaller leaves grow alternately along the stem. The thick, glossy leaves are lanceolate in shape, with acute tips. The leaves have a blue-green color and a leathery texture that gives them a shine. A mature plant spreads over the ground about 0.75–1.5 feet.
Flowers
The many flowers of the plant are large and tubular, opening into a funnel shape. They droop from the point of attachment to the stem, occurring in clusters on the same side of the floral axis. The flowers are approximately 1.5 inches (3.8 cm) long and have an appearance of dropping bells or snipped-off fingers as the common name of the genus, foxglove, suggests. This foxglove is distinguished by its rusty dark-orange to green-yellow coloured flowers. Inside the flowers, red venation and spotting can also be seen as well as tiny hairs at the tips. The arrangement of the flowers in respect to the stalk is racemes and the flowers droop downward.
All parts of Digitalis obscura are poisonous if ingested raw, including the roots and seeds. The most potent parts of the plant are the upper leaves.
All foxgloves are highly toxic if eaten because they contain various cardiac glycosides such as digitoxin, digitalin, digitonin, digitalosmin, gitoxin and gitalonin. During digestion, aglycones and sugar are released by the breakdown of these glycosides. The aglycones directly affect heart muscles and may slow the heart rate until cardiac arrest occurs.
II. How to Grow and Care
Sunlight
The amount of sunlight that spanish rusty foxglove requires depends on your local climate, but typically spanish rusty foxglove loves a shady area to grow in with partial light. The colder your environment, for example, in the north, the more direct sun your spanish rusty foxglove will need. While a mature Spanish rusty foxglove can withstand more shade, it will not thrive in complete shade, and this can affect growth and color intensity of its bloom.
Temperature
Native to Northwest Africa and Europe, spanish rusty foxglove prefers cooler temperatures than hot weather. This plant will happily grow in temperatures between 12 to 28 ℃ with the optimum temperature being around 18 to 20 ℃. If the temperature is over 30 ℃, the plant may start to wilt and die. It can also tolerate winter conditions, thus making it a perfect choice for a range of outdoor environments. Spanish rusty foxglove enjoys moisture but is not tolerant of waterlogging. Supplemental water is needed in dry seasons.
Watering
Spanish rusty foxglove is native to arid regions, hence it has developed a remarkable drought tolerance. It maintains a balance in its water content, neither preferring excessive humidity nor complete dryness. The plant should be watered every week to keep it healthy and thriving. As an evergreen plant, spanish rusty foxglove can retain its foliage throughout the year even with minimal watering, making it ideal for outdoor gardening in temperate climate zones.
Soil
Spanish rusty foxglove can grow in a range of soils, but the optimum soil is a well-draining acidic soil with a pH value of 4.5-8.3. It is recommended to use light and loamy soil which can be purchased from most gardening centers. To ensure spanish rusty foxglove remains happy and healthy, make sure that the soil is neither too dry nor waterlogging at any point.
Fertilizing
Spanish rusty foxglove is a hardy plant that does not necessarily require fertilizer as long as the soil is full of nutrients, or there is a coating of compost on the soil. While this plant can be healthy without fertilizer, many do choose to use it to encourage growth and greater blooms.
In spring and summer, use a water-soluble fertilizer once a month to maintain a nutrient-rich soil which helps the plant to grow. While fertilizer is good for the spanish rusty foxglove, avoid the fertilizer coming into direct contact with the leaves or flowers as the nitrogen may burn the plant.
Planting Instructions
Although spanish rusty foxglove can be planted anytime throughout the year, it is recommended to plant in early spring to allow the plant to settle in warmer weather. Spanish rusty foxglove can grow up to 1.5 m tall and 61 cm wide, so make sure to plant the spanish rusty foxglove with plenty of space around.
This spacing will ensure proper air circulation, which will aid the growth of your plant. As your spanish rusty foxglove can grow to 1.5 m tall, a good tip is to stake the taller spanish rusty foxglove to prevent strong winds knocking it down.
When planting your spanish rusty foxglove, ensure that the top of the root ball is nearly leveled with the surface of the soil. Covering with a good amount of mulch can ensure that your spanish rusty foxglove has access to a lot of nutrients to help it flourish. It is not recommended to plant your spanish rusty foxglove in containers as they can prevent plants from accessing the nutrients that are needed to grow.
Pruning
Spanish rusty foxglove is a biennial flower that will only live for two growing seasons and bloom in the second season. When it reaches the second season, you should notice the buds, also known as spikes, on this beautiful plant before it starts to bloom from the beginning of summer in pink, purple, white and red. As the flowers die, cut the spike from the stalk to encourage further blooms.
Because spanish rusty foxglove easily reseeds itself, be sure to dispose of your spikes away from your compost heap, if you don’t want any more of it. This is to ensure that you don’t start to grow additional spanish rusty foxglove in parts of your garden where you spread your compost. Furthermore, spanish rusty foxglove is poisonous, so make sure to wear gloves while pruning them. If you have pets or small children, it is not advisable to grow this plant in your garden.
Propagation
Spanish rusty foxglove typically reseeds itself so it can be extremely low maintenance to grow it for years. For example, you can leave a dead spanish rusty foxglove on the ground waiting for new plants in the coming year. If you would like to avoid this plant expanding its inventory, it is recommended to deadhead this plant by the end of summer.
It is also straightforward to propagate this plant from seeds purchased from most garden centers. Simply sow the seeds in trays filled with loamy soil in late spring. Make sure not to cover the seedlings and maintain a temperature between 21 to 26 ℃ to allow the seeds to germinate. Germination should take between 4-6 weeks, and once sprouted, transplant them outside by the end of summer. If the temperature is cold, it is recommended to acclimatize your new seedlings for ten days before planting outside.
III. Uses and Benefits
- Ornamental uses
Spanish rusty foxglove is easy to grow, Yellow Foxglove is a welcomed addition to beds and borders or cottage gardens. For best visual impact, plant Floxgloves in groups of 3 to 4 plants.
- Medicinal uses
Digitalis obscura, like many of the other foxgloves, has been used in medicine as a diuretic and to treat heart conditions. For people suffering from heart disease or other heart-related conditions, it can be used to regulate heart rate. In human folk medicine, D. obscura was used for many purposes, such as treating wounds and toothaches. However, the use of herbal medicinal remedies using Digitalis obscura has lessened to a great degree because of the knowledge of its high toxicity.
In ethnoveterinary medicine, the flowering stems of Digitalis obscura were traditionally used to promote wound healing and treat toothaches in animals. It is one of twenty-three species traditionally used in Granada to treat trauma or poisoning in animals.
IV. Harvesting and Storage
Due to its colorful bloom, some people harvest the flowers of the spanish rusty foxglove. These flowers will be harvested at the beginning of summer. When you are gathering its flowers, it is advisable to wear gloves.
Spanish rusty foxglove is used as an ingredient for a form of heart medication and is commercially harvested throughout the year. Unless you are a trained medical expert, do not try to harvest or administer this for medication purposes. If you accidentally ingest this plant, please seek medical help immediately.
