Digitalis ferruginea
SPECIMEN · FROM THE LIBRARY
Digitalis ferruginea

Digitalis Ferruginea

ON THIS PLANT

Digitalis ferruginea, commonly known as rusty foxglove, is a perennial herbaceous plant belonging to the Plantaginaceae family. Native to the Mediterranean region, it thrives in rocky areas, meadows, and forests. The plant can reach a height of up to 1.5 meters and features lance-shaped leaves that are hairy on both sides.

The flowers of Digitalis ferruginea are bell-shaped with a rusty orange exterior and a yellowish-white interior. They bloom in late spring or early summer, attracting bees, butterflies, and hummingbirds.

Historically, the plant has been used for medicinal purposes due to its cardiac glycosides content, making it useful in treating heart conditions such as congestive heart failure and irregular heartbeat.

Digitalis ferruginea requires well-drained soil and thrives in full sun or partial shade. While it is drought-tolerant, regular watering during dry periods is essential for optimal growth.

Overall, Digitalis ferruginea is an attractive ornamental plant that adds color to any garden while also offering medicinal benefits, making it a valuable addition both aesthetically and functionally.

A note from PlantMom

Rusty foxglove is fairly disease-resistant and typically not susceptible to illnesses. Nonetheless, it can be affected by pests and diseases found in its environment. Such infections are generally mild. Regarding care, this plant requires moderate maintenance. It should be pruned regularly to keep a pleasing appearance and support healthy growth. Applying fertilizer can also encourage flowering. Rusty foxglove is suitable for anyone with an outdoor area, such as a garden or patio, and does not demand extensive gardening experience. It may need more attention when grown indoors.

— PlantMom
CARE GUIDE

How to keep Digitalis Ferruginea.

Light

Rusty foxglove does best in places with limited sunlight but can adjust to areas that are either very sunny or very shady. Coming from habitats with a blend of sun and shade, rusty foxglove grows most successfully in those conditions. Too much sun or too little light can harm its development, resulting in stunted growth or leaf burn.

Water

The rusty foxglove requires moderate watering each week to maintain consistent moisture levels. It thrives in well-drained soil, which helps prevent waterlogging. This plant is typically found in regions with balanced humidity, as it has limited drought tolerance. It is commonly grown outdoors as a herbaceous perennial.

Temperature

Rusty foxglove is native to temperate regions and prefers climates with temperatures between 68 and 95 °F (20 to 35 ℃). During colder seasons, adjust the temperature to more closely mimic its natural habitat and promote growth.

Fertilizer

The best time to fertilize a Rusty foxglove is in early spring, as it comes out of dormancy and begins active growth. Fertilizing supplies the essential nutrients needed for healthy growth. Although Rusty foxglove requires relatively little fertilizer, feeding it once a year can improve its survival and encourage better, longer-lasting blooms.

Pruning

Rusty foxglove has tall spires adorned with rust-colored flowers. To promote new growth and a bushier appearance, prune them from early to late spring by removing spent flower stalks and cutting back the foliage after flowering. Proper pruning enhances the plant's overall vigor, ensuring a vibrant display in future seasons.

Toxicity

As with many poisonous plants, foxglove is poisonous to both people and pets. The plant contains cardiac glycosides such as digitoxin, digoxin, and digitalin. The foxglove plant is actually the source of the heart medication known as digitalis. The therapeutic dose is dangerously close to the lethal dose, so administering the medication requires careful monitoring by a doctor.

Further reading →

The toxicity and danger assessments provided are for reference only. We do not assure their accuracy, so it's crucial not to depend on them. Seek professional advice when necessary for accurate guidance.

CHARACTERISTICS

Botanical profile.

Plant Type
Herb
Life Cycle
Perennial, Biennial
Genus
Digitalis
Family
Plantaginaceae
Hardiness Zone
4-9
Mature Height
0.91 m to 1.52 m
Mature Spread
40 cm
Leaf Color
Green
Leaf Type
Evergreen
Flower Color
Tan
Flower Size
5.08 cm to 7.62 cm
Bloom Time
Early summer, Mid summer
Planting Time
Spring, Summer, Autumn
Harvest Time
Late summer, Early fall
Native Area
Hungary, Romania, Turkey and the Caucasus
ALSO KNOWN AS

Other names.

en Rusty foxglove
FREQUENTLY ASKED

Reader questions.

How should I water my Rusty foxglove plant?

To ensure the wellbeing of the Rusty foxglove plant, it is important to follow these watering guidelines. Firstly, it is recommended to use filtered water that is at room temperature. This is because tap water may contain harmful particles that can affect the plant's health. Additionally, the water should be at room temperature or slightly warmer, as the Rusty foxglove is native to warm environments and cold water can be too much of a shock for it. Also, it is advised to refrain from overhead watering as it can cause issues with the foliage. Instead, it is preferable to apply the filtered room temperature water directly to the soil until it is thoroughly soaked. This method helps to moisten the plant's roots and promotes their spreading and nutrient absorption in the soil.

Why should I put fertilizer on my Rusty foxglove?

The Rusty foxglove relies heavily on its leaves for structure. Fertilization plays a crucial role in maintaining the appearance and function of these leaves. By fertilizing properly, you can ensure that the leaves of your Rusty foxglove have consistent color and a healthy texture. Fertilization also has benefits beneath the soil's surface. It encourages the development of new roots and helps maintain existing ones, making your plant better equipped to absorb soil nutrients in the long term. In short, proper fertilization not only keeps your plant healthy now but also enhances its ability to thrive in the future.

What are the sunlight requirements for Rusty foxglove?

Rusty foxglove thrives in environments that receive a range of sunlight, from areas with sparse sunlight to those where sunlight is more predominant. Ideally, this plant does well in conditions that mimic its native habitat—areas with a mix of sun and shade. While it can adapt to different amounts of light, both insufficient light and excessive sunlight can negatively affect its growth. The plant needs about 3-6 hours of sunlight for partial sun conditions and more than 6 hours for full sun or full shade conditions. It's crucial to observe the movement of sunlight through your garden to select the best spots that provide the right balance of light and shade.

What temperature is best for Rusty foxglove?

The ideal temperature for Rusty foxglove depends on the time of year. There are two main seasons to consider: the growing season and the dormancy season. During the growing season, which is when the plant starts to sprout, the best temperature range is between 65 to 80℉ (18 to 27℃). If the temperature drops below 15℉ (-10℃), the plant may suffer, with its leaves browning and wilting. However, if it's only a short cold snap, with some assistance, Rusty foxglove might survive. On the warmer days of the year, it's also important to protect Rusty foxglove from excessively high temperatures. Any temperature above 95-105℉ (35-40℃) can harm the foliage and blooms of the plant. This can result in wilting, drooping, and even sunburn on the leaves, which can be challenging for Rusty foxglove to recover from. Luckily, there are simple and quick ways to deal with this issue.

What should I do if I give my Rusty foxglove plant too much or too little water?

Overwatering and underwatering can both harm your Rusty foxglove, but overwatering is more common. Excess water can cause wilting, yellowing leaves, and even diseases like root rot, mold, and mildew that can be fatal to the plant. Underwatering is less likely, as Rusty foxgloves can tolerate drought quite well, but it can still happen. In this case, the leaves may become dry and brown. It is crucial to recognize the signs of overwatering early on. Some diseases caused by overwatering, like root rot, may be irreversible if left unattended. Reduce your watering schedule immediately if you notice any early signs. Also, check the soil's quality. If it drains poorly, replace it with a loose, well-draining potting mix. Conversely, if your Rusty foxglove shows signs of not getting enough water, simply water it more regularly until the signs disappear.

When should I fertilize my Rusty foxglove plant?

If you grow your Rusty foxglove outdoors, it will start growing new leaves in early spring, indicating that it's time to fertilize. Usually, one application of fertilizer in spring is enough for the plant to thrive. However, if you want to maximize growth, you can fertilize multiple times in spring and early summer. In this case, you can feed the plant once every month to a month and a half.

How should indoor Rusty foxglove plants be lit when natural light is insufficient?

When natural sunlight is insufficient, especially during winter or in less sunny spaces, artificial lighting becomes essential for Rusty foxglove's growth indoors. LED lights are recommended because they can be tailored to provide specific wavelengths needed by plants. The amount of artificial light needed varies based on the type of plant: 30-50W/sq ft for full sun plants, 20-30W/sq ft for partial sun, and 10-20W/sq ft for full shade plants. The ideal placement of the light source is 12-36 inches above the plant, and it should be turned on for 8-12 hours a day to mimic natural daylight hours.

What temperature does Rusty foxglove need in its first year or as a seedling?

If you have a Rusty foxglove plant outside for the first time, it may need some extra care during the coldest months. Frost can be very damaging to a first-year Rusty foxglove and may prevent it from growing back healthy in the spring. To protect the plant, you can keep it at a temperature of 40℉(5℃) or above by either bringing it inside for a month or two or using mulch or fabric barriers to keep it safe from frost. During the first year or two, it's a good idea to plant the Rusty foxglove in a shadier spot. Smaller and weaker plants struggle more to regulate their temperatures in the heat, so they need less direct sunlight. Five hours of direct sunlight per day is sufficient, especially if the temperature goes above 80℉(27℃). To control the summer heat, you can use shadecloth and water or mist the plant frequently.

How frequently should I water my Rusty foxglove?

To determine if your Rusty foxglove plant needs water, follow these steps based on whether it is in a pot or grown outdoors in the ground. For potted plants, check the soil moisture by inserting your finger into the soil. If the top two to three inches are dry, it's time to water. The same method applies for outdoor plants, with the first few inches of soil needing to dry out before watering. Typically, this plant should be watered once a week during spring and early fall. In very hot weather, watering may need to be increased to twice a week. However, mature, well-established Rusty foxglove plants have a remarkable ability to tolerate drought.

When is the best time to not add fertilizer to my Rusty foxglove plant?

During late fall and winter, your Rusty foxglove will be dormant and will not grow. So, avoid fertilizing it during this time. In spring and summer, you can fertilize it multiple times, but as summer approaches, reduce the amount of fertilizer because the growth rate of the Rusty foxglove will slow down. It's not a good idea to fertilize the Rusty foxglove during extremely hot weather or when the soil is very dry. Fertilizing in these conditions can stress the plant and cause it to die earlier.

What are the signs of light deficiency in Rusty foxglove?

Signs of light deficiency in Rusty foxglove include smaller than usual new leaves, leggy or sparse growth, faster leaf drop, slower or no new growth, and lighter-colored or pale new leaves. Additionally, symptoms like chlorosis, which is the yellowing of leaves due to chlorophyll breakdown, sunscald marked by pale or necrotic spots, leaf curling as a defense against excessive sunlight, wilting from rapid water loss, and leaf scorching indicated by brown, dry patches on leaves, can all suggest the plant is not receiving the appropriate amount of light.

How can I keep Rusty foxglove safe from really hot or really cold weather?

If you experience cold temperatures below 15℉(-10℃) while growing Rusty foxglove, there are a few steps you can take to protect it from frost damage. If you have the plant in a container, simply bring it indoors to a location with bright, indirect light until temperatures rise above the lower threshold. For ground-planted Rusty foxglove, you can use mulch or horticultural fabric to create a protective barrier around the plant, shielding it from frost and cold winds. In hot temperatures exceeding 80℉(27℃) in the shade, it's important to limit the amount of direct sunlight the Rusty foxglove receives, especially during the hottest parts of the day. To achieve this, you can put up shade cloth or use a fine plastic mesh to reduce direct sunlight. Additionally, installing a misting system that releases a slow stream of cooling mist around the plant's base during the day can help lower ground temperatures.

PLATES
Digitalis ferruginea leaf
PLATE 01 · leaf
Digitalis ferruginea leaf
PLATE 02 · leaf
Digitalis ferruginea flower
PLATE 03 · flower
Digitalis ferruginea flower
PLATE 04 · flower
Digitalis ferruginea fruit
PLATE 05 · fruit
Digitalis ferruginea fruit
PLATE 06 · fruit
ALSO IN THE LIBRARY

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