Globe Thistle: How to Plant, Grow, and Care For Echinops
If you are looking for a beautifully unique blue flower that adds some variety to your garden, look no further than the globe thistle. This unique plant has some strikingly beautiful blue flowers, and is fairly easy to care for depending on your hardiness zone. In this article, gardening expert Madison Moulton walks through how to plant, grow, and care for this amazing plant.
A perennial garden is incomplete without Blue Globe Thistle. This flowering plant is native to southern and eastern Europe and western Asia. As part of the sunflower family, this plant is sure to create a summer spectacle with a spectacular twist.
It is mainly sought after for its spherical, spikey flowers that come in beautiful hues of blue. Unfortunately, these pretty spines do sting when they come into contact with the skin.
On top of its summery looks, there are several benefits to growing this plant. It’s very fast-growing, adaptable, and easy to care for, thriving in almost any condition. They are also drought tolerant and deer resistant. Plus, they attract a myriad of beneficial insects. Butterflies in particular are fans of its spiky foliage, as it’s a delicious source of food for them.
This summer-blooming beauty continues to add textured interest in fall with its striking seed heads. Blue globe thistle looks most at home along beds and borders in cottage gardens and meadow-style landscapes. However, they can also add splashes of color in rock and gravel gardens.
Blue Globe Thistle Plant Overview
Plant Type Perennial
Species Echinops bannaticus
Native Area Europe and Asia
Hardiness Zone USDA 3-9
Season Summer and Fall
Exposure Full Sun to Partial Shade
Maturity Date Two Weeks
Growth Rate Fast
Plant Spacing +/- 2 feet
Planting Depth 1 inch
Height 3-4 feet
Watering Requirements Low
Pests and Diseases Aphids, Root Rot, Powdery Mildew
Tolerance Drought, Deer, Rabbits, Dry Soil
Soil Type Well-draining
Plant With Yarrow, Echinacea, Alabaster
Don’t Plant With Water Dependent Plants
Plant History and Cultivation
Throughout history, globe thistle was a popular plant – not typically for its looks, but for its medicinal properties. The roots were mainly used by herbal practitioners for their anti-inflammatory and lactation-promoting capabilities, predominantly used to treat mastitis and breast swelling.
Globe thistle was first named in the 1700s by renowned Swedish botanist Charles Linnaeus. He aptly named the genus Echinops, which is a Greek word that roughly translates to ‘hedgehog head’. Echinops is a large genus, consisting of over 120 different globe thistles. The most popular is Echinops ritro, which was one of the few that made their way into home gardens.
Echinops were eventually introduced to the United States in the 1800s, and since then has spread across North America. The blue globe thistle has won several prestigious gardening awards, including the Royal Horticultural Society’s Award of Garden Merit.
Blue is not a common color in the flower world, so this plant, with its steely blue spikes, is a popular choice amongst gardeners.
Propagation is done in one of three ways – seeds, roots, and division. No matter the method you choose, remember to wear thick gloves to protect your hands from the sharp spikes.
Propagating From Seed
Propagating from seed is not the most common method, but it is the easiest. Blue globe thistle, like most thistles, self-seeds every fall, creating a post-summer textured spectacle.
Gather the seeds by removing the seed heads and gently shaking out the seeds. Their seeds, like many perennials, require a cold treatment or stratification before they can germinate. This mimics the natural process many seeds go through during winter before they germinate.
You can go the natural route and sow your own seeds outdoors during winter. But, you can still sow your seeds indoors and easily replicate the stratification process. Simply place your seeds on a tray, cover them in plastic, and pop them in the fridge for a few weeks. You’ll also need to water your seeds now and then to maintain water and humidity levels.
It’s advised to sow indoor seeds about two months before the last frost. Once the seeds have experienced their cold period, they’re ready to move into pots or trays. Fill these with a seed starter mix and gently press the seeds into the soil. Next, add a thin layer of compost over the seeds.
Place the pots or trays in a spot that receives filtered light and water them. Cover your containers with plastic to trap humidity. Water your seeds when the soil becomes dry to the touch and maintain a temperature of about 70F.
The seeds will begin to sprout in about two weeks. Once the frost clears, your seeds will be ready to be transplanted outdoors.
Propagating From Roots
Blue globe thistle can also be propagated from root cuttings. While this is the most common method, it can’t be done on younger plants. Your plant needs to be at least three years old, with an established root system. This method is also best done during the plant’s dormancy, which is between late winter and early spring.
To successfully propagate from roots, carefully dig up about six inches of the plant to expose its root system. Next, cut off a lateral root at the thickest section using clean, sterilized pruners. This helps prevent the spread of disease. The root cutting should be around five inches.
Replant the parent plant and gently tamp down the surrounding soil. Next, gently wash away any soil and debris.
You can dip the cut end of the root into some rooting hormone powder to help stimulate root growth. Next, lay the root cutting horizontally in about three inches of soil in a sunny location. Water your new planting thoroughly and frequently to maintain moisture levels.
You’ll know your propagation was successful when you spot new green growth.
Propagating by Division
Blue globe thistle can also be propagated by division in spring or fall. This method requires an established, three-year-old plant with plantlet growth at its base. Making this method even more challenging, is the long, thick taproot that can make reestablishment a struggle.
The length of these roots is difficult to judge and could mean plenty of digging. If you’re up to the challenge, gently uproot the entire plant and brush off excess soil and debris.
Using a sharp, clean knife, cut down the taproot so that each plant has some taproot and lateral roots. Next, replant the divided plants at the same depth as the original host plant.
Planting is as easy as caring for this plant. Transplant seedlings in spring when temperatures begin to rise. To prevent transplant shock and give your new plants a strong start, there should be no looming frost around the corner.
First, prepare the chosen site for planting by loosening the soil and clearing away any weeds and debris. Next, dig a hole that is slightly wider and deeper than its projected size.
This plant will flourish if its roots are given sufficient space to grow. Mature plants can also grow as tall as 4 feet, with a spread of about 2 feet. They need plenty of space to spread and thrive when planting multiple plants. Space each transplant at least 2 feet apart. For the time being, your bed may look sparse, but it will fill out in no time.
Blue globe thistle root cuttings can simply be planted in a desired, sunny location, and they’ll grow quite successfully. Similarly, a divided plant will flourish just as easily if replanted at the same depth as the original plant.
All new plantings should be watered thoroughly but slowly. This method allows the water to penetrate lower levels of the soil. Keep the soil well-watered until the plants are established.
Planting in Pots
Blue globe thistle does look most at home in flower beds in cottage gardens. But they make just as much of a statement in containers, perfect for patios and those with limited space. It’s also an easy way to control the rapid growth and spread of these plants.
These plants will grow best in a well-draining pot big enough to accommodate its long taproot.
This plant requires a well-draining soil mix, such as cactus potting soil. Garden soil is unfortunately not suitable for container plants as it doesn’t provide the necessary drainage, often becoming compacted.
This striking perennial is known for its low-maintenance nature, but it does require some added TLC when planted in containers, such as extra watering.
How to Grow
Blue globe thistles are notoriously easy-going plants. They generally face few issues and are even drought tolerant once established. While they’re not very fussy plants, there are a few things to keep in mind when deciding if this plant is the right fit for your garden.
As mentioned, echinops are lovers of the sun. They look their best, remaining compact and blooming well, with at least six to eight hours of sunlight a day. The added sunlight also increases water evaporation, which dries the soil faster and limits the chances of disease.
Blue globe thistle does appreciate partial shade in the afternoons when grown in extremely hot climates.
Blue globe thistle’s low water needs add to its low-maintenance charm. It doesn’t need a lot of water to thrive and once established, is drought tolerant.
Its long taproot allows it to access deeper parts of the soil where water does not evaporate as easily. The topmost layers of soil can remain dry, and your plant will remain satisfied. However, prolonged periods of drought can cause stress, resulting in browning leaves.
For a healthy garden, it’s always best to maintain a consistent watering schedule. You should allow the top layer of soil to dry between watering, only increasing or decreasing the frequency depending on the weather. Long periods of heat call for more water, while cooler temperatures or rainy periods require far less water.
Blue globe thistle is happy in most soil types, as long as it’s well-draining. Planting them in raised beds or amending the soil with sand can help facilitate drainage. Coconut husk and river sand are great additions to heavier, low-draining soils.
Generally, echinops can thrive in poor soil conditions, including dry, rocky soils.
Well-draining soil, together with the correct watering methods prevent some of the diseases that they are prone to.
Climate and Temperature
Blue globe thistle grows in a range of climates under USDA zones 3-9, but they prefer and grow best in, hot, dry climates. When planted in areas with excessive heat, they will appreciate some shade and extra water, but they will certainly look their happiest there.
If grown in a high humidity area, ensure adequate spacing between the plants. This helps prevent the growth of powdery mildew.
Blue globe thistle is one of a few plants that prefer poor quality soil. Not only does it require very little water, but it also doesn’t need to be fertilized.
Fertilizer and extra nutrients can make them leggy and often encourages spreading. Avoid anything that encourages the rampant spread, as this fast-growing perennial can quickly become invasive.
Blue globe thistle is the perfect eye-catching perennial for the low-maintenance gardener, requiring very little maintenance. They may need staking if stems appear floppy. This floppiness is either caused by excessively fertile soil or heavy seed heads.
Pruning throughout the growing season is only necessary for a handful of reasons. You can snip flowers to add them to a cut flower bouquet, for example. Spent flowers can also be pruned away to encourage a second bloom. Those living in areas with high levels of humidity need to prune more often, as it improves airflow and decreases the chances of disease.
Other than that, echinops only require a touch of maintenance at the end of the season. Deadheading the plant prevents self-seeding, which may be needed to prevent their uncontrolled spread. It’s best to cut the plant down to ground level in early winter.
For some added winter protection, you can add a thin layer of mulch around the base of the plant.
Varieties and Cultivars
Echinops can bloom in either steely blue, deep purple, or snow white. The blue options, however, make a striking statement and are highly sought after, since blue is a rare natural color. For a sure blue globe thistle, opt for created blue cultivars.
The deepest blue cultivar is ‘Veitch’s Blue’. The globes of ‘Veitch’s Blue’ are a dark blue that is offset perfectly by silvery stems. This brilliant contrast is further highlighted by ‘Veitch’s Blue’s’ dark foliage. This dark blue cultivar is perfect for those chasing dark blue flowers and the striking look of this flower.
‘Taplow Blue’ is another beautiful blue cultivar, but its blooms are more muted than ‘Veitch’s Blue.’ They’re a softer, steel-blue color that is brightened by the long, white, leafy stems. ‘Taplow Blue’ is also a taller cultivar, reaching about 5 feet. It’s perfect for the back of borders, where the striking globes can tower over other, softer flowering plants.
Echinops bannaticus ‘Blue Glow’ may not be as dark as some other cultivars, but they’re just as striking. This variety’s blue globes sit atop long, silver-green stems filled with sharp, silvery foliage. ‘Blue Glow’ is more unique than other varieties, as its striking globes are not prickly.
Echinops ritro subsp. ruthencius (small globe thistle), is a subspecies of the globe thistle that boasts bright blue-purple globes. Their flowers are offset by white stems and glossy silver foliage. It’s a shorter plant, only reaching about 3 feet – perfect for containers or the front of borders.
Pests and Diseases
While globe thistles aren’t bothered by many pests and diseases that other plants in different families are, they do have some that they are susceptible to. Let’s take a look at what you can expect when preventing a pest infestation, or any diseases that may try to attack your plants.
Globe thistles aren’t typically bothered by pests and are luckily both deer and rabbit resistant. Their striking blue globes attract pollinators, particularly butterflies, which love to munch on the prickly blooms. Unfortunately, there are a few pests that love these plants as much as butterflies, namely aphids, the four-lined plant bug, and Echinops leaf minor.
Aphids are a common garden pest that will nestle themselves under the foliage of most flowering plants, globe thistles included. An aphid infestation can quickly get out of hand if left unattended. Luckily, managing and avoiding an aphid infestation is an easy task.
Adding checking the undersides of leaves to your daily gardening routine, aphids are easy enough to spot. If you do notice an aphid or two (or any other bug), simply squish them between your fingers. Larger aphid colonies can be managed by using horticultural sprays, like neem oil. Bear in mind that neem oil can deter pollinators, despite it being a great natural pesticide. You can also opt to introduce aphid predators into your garden, like ladybugs, to prey on aphids.
Horticultural sprays and natural predators are also the main line of defense against Echinops leaf miners. Diglyphus isaea, or leaf minor parasite, is a small black wasp that kills leaf miners. They’re available to purchase at many nurseries.
The four-lined plant bug is less of a worrying pest, as its damage is mostly aesthetic. However, you can easily avoid having the beauty of your globe thistles marred by removing any bugs off the leaves. Horticultural sprays help get rid of this pesky pest, too. Luckily, the life span of these bugs is very short-lived, so there is little chance of a full-blown infestation.
While they aren’t prone to any serious diseases, root rot and powdery mildew can occur. These fungal diseases usually occur if the plant is constantly exposed to wet, soggy soil and high humidity levels.
Powdery mildew rarely affects this plant, but it can have devastating effects on your plants. This fungus causes a white, powdery mold to grow on plant foliage. It can quickly spread, resulting in leave wilt and drop, and, in severe cases, the death of the plant.
Root rot symptoms are easy to spot, as the base of the plant stem typically turns yellow. The striking silvery foliage may also begin to wilt and wither.
Luckily, both root rot and powdery mildew are quite preventable. Ensure the correct plant spacing is maintained so that sufficient air can move through the foliage. Pruning also improves air circulation.
Maintaining good garden hygiene is another easy preventative measure. Remove any debris around the base of your plants and only use clean gardening tools. You should also avoid overhead watering and overwatering.
Blue globe thistle has a place in every garden, no matter the landscape design. They’re typically grown for their striking globes and showy foliage, both of which add unique texture and color to your garden. An echinop’s ability to thrive in low-quality soil makes it perfect for rock gardens. It’s also a great contender for xeriscaping – desert-style landscaping best suited for hot, dry climates.
Their spiky flowers break up the softness of traditional cottage gardens, especially when planted along borders. Depending on your chosen variety, you could position them upfront or along the back of your border. This plant pairs well with bright flowering plants, like Asters or black-eyed Susans, whether in borders or containers.
They are also a wonderful addition to cut flower gardens, as its pretty globes and white stems make wonderful cut flower bouquets.
Frequently Asked Questions
Is this plant considered invasive?
While they are not listed as an invasive species, its self-seeding nature does cause it to spread quickly. If left unmaintained, it can quickly run wild and take over spaces. You can control the spread by cutting it back at the end of every season.
Should I deadhead blue globe thistle?
Deadheading throughout the growing season allows for a second bout of globes to bloom. It also allows you to maintain the spread of this rapidly growing perennial.
What season is best for planting?
The best time to plant this particular flower is in late spring or early summer.
Why is my plant not blooming?
These plants are usually worry-free, low-maintenance plants, but the wrong conditions can prevent blooming. Typically, heavy clay soils that don’t drain well and constantly wet conditions are the main reason why they don’t bloom. Ensure your plant is planted in well-draining soil or amend your soil with river sand to improve conditions.
Lack of sunlight can also prevent blooming. These plants love sunny spots and need plenty of energy to produce their impressive flowers. Give your plant at least six hours of sunlight a day to ensure healthy blooming.
If you’re happy to control its spreading nature by cutting it back every season, blue globe thistle deserves a spot in your garden. It is the perfect textured plant for new green thumbs and the seasoned gardener alike.
This plant’s ability to thrive in almost any condition allows gardeners to utilize their creative flair in any area. Whether it’s in a rock garden, a traditional cottage garden, or a modern container garden with desert-style plants, this plant can flourish.