How to grow thistle?

ECHINOPS RITRO

Small globe thistle, Echinops ritro, is a perennial member of the Asteraceae family that includes sunflowers and globe artichokes.

Also called Southern globe thistle, this wildflower is native to Europe and Asia.

The Echinops group is a broad one with many subspecies, including the blue, E. bannaticus; the great, E. sphaerocephalus; and the tall, E. exaltatus, varieties. The most noteworthy differences among them are color, size of the flower heads, and height.

Some are naturalized across the US, most notably E. sphaerocephalus, which is considered to be a noxious weed in Illinois.

Ornamental and Practical

Small globe thistle is a sturdy and attractive flower. Its compact, round flower heads are approximately one and one-half to two inches in diameter, or about the size of a golf ball. Each one perches atop a spiny-leafed stem.

E. ritro ‘Veitch’s Blue’

This plant grows with full sun in dense clumps, reaching over three feet in height. It makes a striking ornamental accent, an eye-catching anchor for smaller foreground plantings, and a stunning monochromatic display when planted en masse.

Small globe thistle is not only attractive, it’s low maintenance too. Once established, its water needs are modest. It’s also drought tolerant, making it a practical choice for xeriscaping, in which plants thrive with minimal care and moisture supplementation.

Please Note: This plant has a thick and lengthy taproot, so be sure to plant it where you want it. Once it takes hold, it may be very difficult to successfully relocate.

E. ritro Plant Facts

  • Average to dry soil
  • Blue
  • Drought-tolerant
  • Full sun
  • Heights exceeding 3 feet
  • Introduced species
  • Late summer bloomer
  • Perennial
  • Zones 3 to 8

Where to Buy

Small globe thistle seeds are available on Amazon from Hirt’s Gardens.

Echinops Ritro Globe Thistle Seeds

Each package contains 50 seeds for plants with violet-blue flower heads that reach a mature height of between 2 and 4 feet.

A Cut and Dried Winner

E. ritro is a fun plant to grow. Our kids love the whimsical pom-poms, and how they tower over the littlest among them.

And, besides being a great xeriscape plant, it’s a must-have for the cutting garden.

What’s not to love? This plant deserves a place on your garden to-do list, for sure!

You’re going to enjoy small globe thistle, especially late in the summer, when other flowers begin to fade.

There’s no garden project more rewarding than harvesting, and I don’t just mean vegetables and fruit. Arranging foliage from the garden is fun for the whole family, especially when the flowers are an amazing shade of blue.

For enjoyment through the winter months, this flower may be dried for use in decorative arrangements. Please see our article, “Anise Hyssop is a Honey of an Herb in Border Gardens,” for instructions.

We like to hear from our readers. Are you familiar already with the plant featured in this article, or is a new one to you? Tell us about your experiences in the comments section below, and follow us on Facebook for more gardening ideas you can use at your house.

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Product photo via Hirt’s Gardens. Uncredited photos: .

About Nan Schiller

Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!

How to Grow Echinops

Growth Habit: Echinops is an upright, clump-forming perennial that has thistle-like texture (thorns included) and a large taproot. It blooms from July to August with a spiky golf ball-sized flower head. The sometimes-branching stalks grow from a basal foliage rosette. If it is in a desired location, it readily self-sows, so your plant could start to naturalize an area. If that’s not the desired intention, Echinops blooms can be deadheaded (snipped off) before the seeds fall to easily prevent this occurrence.

Staking: Species that are 4 feet tall or less typically do not need to be staked. The stalks are very strong and durable. Staking might be necessary for taller species or stems with particularly large flower heads that can weigh it down.

Watering: Echinops is fairly drought-tolerant. Once the plant is established, it should perform great without any supplemental watering. However, during its first season of growth and directly after being planted, it should be watered regularly until it is established.

Fertilizing: No fertilizing is necessary as Echinops performs well in nutrient-poor soils. It will not harm the plant to have a mild slow-release fertilizer applied in spring if desired.

Trimming/ Pruning: Without any deadheading, Echinops will readily self-sow and spread throughout an area. To reduce self-sowing, Echinops can be deadheaded after flowering. To do so, simply cut the seedhead stalk down to the basal foliage. Deadheading early enough will encourage an additional autumn bloom.

Mulching: Mulch is not required for Echinops, as this species does well in soils with low organic matter. However, it is beneficial to have a thin layer of mulch in a garden bed to insulate, allow for water percolation, and suppress weed seeds from germinating. Though it is not essential, Echinops would be happy with this beneficial thin layer of mulch.

They are topping the meadow the other side of our boundary hedge. The tractor is cutting the thistles with regular sweeps, slowly accruing the field. This, as surely as any calendar, is one of the hundred markers of my year. I cannot claim any private fine-tuning of sensibility in this – thistles have been a country-diary marker as constant as the first swallow or cuckoo. The old rhyme is Cut thistles in May, they’ll grow in a day; Cut them in June, that is too soon; Cut them in July, then they will die.

If left until August, the fluffy white down of the the seeds floats across the fields like river mist, spreading tens of thousands of thistle seeds with the wind, hundreds of which seed in this garden. They love our heavy soil, and on the whole are an indicator of a good, deep topsoil.

So, if you are coming to a new, overgrown, be-thistled garden, take heart – it is nature’s own seal of soil approval.

The British thistle family (Cardueae) are part of the large daisy mob, and include knapweed and cornflower from their centaurea section, the spear thistle, creeping thistle and fabulous Cirsium rivulare ‘Atropurpureum’ from the cirsium branch, and burdocks (arctium).

The garden, of course, has many other thistles, but they have all been introduced at some time or other. The spear thistle, C vulgare, is the one that is the common weed in these parts, developing spines like needles and the characteristic ‘Scotch’ thistle flower. Although the farmer may not cut it until July, the gardener wants to get it out long before then, even if it comes back for a second go, because, when young, it can go on the compost heap, but as soon as the spines harden up it must be burnt.

Its close cousin, the creeping thistle C arvense, has a soft, sappy stem which has a habit of snapping off when you try and pull it up. It tends to get in under the hedges of this garden, spreading by lateral roots as well as by seed. We also get a lot of sow thistles at this time of year (Sonchus asper and S oleraceus) which are sappy and easy to pull up in well-cultivated soil, and then compost. All thistles can be eaten, but these are best, with the young leaves added to a salad having cut off the prickly bits. They produce an enormous amount of seeds and I have just read – to my astonishment – that if the weed is hoed off and then subsequently buried while in flower, the flowerhead will mature and produce seeds underground, which then germinate when the soil is turned over again.

Also, it is host to lettuce-root aphid, which we got here for the first time last summer. I thought then that it was the curious mixture of wet air and dry soil, but perhaps it was these thistles. The other intrusive thistle into this particular garden is the burdock. It grows to at least 6ft on this rich soil and the burrs snag appallingly on jerseys all winter long. The answer is to cut it at ground level as soon as you see it and to go on doing so until it weakens and dies. But there are a lot of uses for it – the leaves can be used to wrap butter in, and the young shoots can be peeled and eaten raw and the roots made into dandelion and burdock beer – which I can remember being sold everywhere 30-odd years ago.

The obviously edible thistles in any garden are artichokes (Cynara scolymus) and cardoons (C cardunculus), although I suspect not many people bother to eat cardoons nowadays. We grew a batch as a vegetable a year or two back, planting them in blocks and wrapping each one in a cardboard sleeve to blanche the stalks, which is the bit you eat. They looked very good in the winter vegetable garden but we ate very few. They had the texture of stringy celery and the taste of artichokes. Not bad, but 50 times the trouble of chard, whose stalks have the same culinary role. And if you want artichoke taste, then grow artichokes.

Four years ago I wrote a piece in this magazine about thistles, and gave the impression that cardoons and artichokes were a doddle to grow as long as the latter had protection from frost. But I would qualify that now in the light of recent years’ experience. This year, for example, our cardoons have not had anything like the vigour of previous years, save for the new plants grown from seed last year. I suspect that this might be the combination of sodden ground and the intense cold we had in January. They are, after all, a Mediterranean plant, and anything from that region hates sitting in cold, wet soil. However, every garden should have at least one, and you can easily propagate from this every year by taking side shoots off each April, cutting down with a sharp spade to separate it from the parent plant. The flowerheads are lovely, but if you want to get the most foliage-power from the plant, cut off the flowering stems as they appear.

Artichokes are similar to cardoons, but are smaller and more tender and, whereas a cardoon will (weather permitting) happily grow on for decades, artichokes rapidly lose vigour and the ability to produce flower heads after three or four years. As the immature flowerheads are the bits you eat, the trick is to replace the crop every four years – rather like strawberries. Like cardoons, they grow easily from seed, but often do not come true to parent type, so sideshoots are a more reliable means of producing new plants. For the first year you should cut off any flowerheads as soon as they appear, to let the plant build up strength. Harvest them in years two and three, and ditch the plant thereafter. This means having a line of plants in the vegetable garden doing nothing for a year, but it is worth it. They need protective mulching in winter.

There are gardeners who regard the giant cotton thistle Onopordum acanthium as a weed, but I love them and carefully dig up the seedlings where they pop up in clusters and redistribute them for better effect. They are intrusive, growing to at 6ft – and often half as much again – with a spread of 4-5ft. But they are among the most magnificent plants that any garden can grow, with huge grey leaves coated with a milky down fringed with wicked spikes.

It needs strong staking or else it will be brought crashing down like a felled tree in the first summer gale. It is biennial, and the best way to get plants is to dig up unwanted seedlings from a friend – they seed everywhere – and plant them. Get on with it because they develop a long tap root which will not tolerate moving much after the end of this month. June is the best time for the job. When the plant has flowered it rapidly becomes a spectacular skeleton which, if supported, looks fine, but makes weeding a nightmare as the spikes get spikier with age.

If you have a very well-drained soil then you might grow another Caucasian thistle, Centaurea ‘Pulchra Major’. This is much more refined than onopordum but a good plant, flowering for a long time in mid-summer, and the felted, grey leaves provide important foliage to the border. I will not try it because it would hate our wet clay.

C rivulare ‘Atropurpureum’ became suddenly trendy last year, despite the fact that a lot of people have been growing it for years. But I had not, and we put one in the Jewel garden last year where it produced its plum-coloured flowers and seemed positively cosy. This year it started out fine, but then collapsed dramatically a month or so ago. There seems to be no explanation for this, but it’s still alive and I see that Christopher Lloyd, in his Garden Flowers (£30, Cassell), says that it is prone to ‘sometimes failing when you least expect it.’ We shall see.

The globe thistle (Echinops ritro) is as tough as artichokes are tender. Nothing seems to stop it, including my efforts to dig up a plant that has lodged in the vegetable garden for six years. It only needs a scrap of root to regenerate itself, laughing scornfully. But I love its perfectly round mauve heads, that have a weirdly functional moment just before the buds open, when they look like steel tooled to industrial specification. It is a tough, herbaceous perennial, happiest in poor soil as long as it gets some sun, and though its leaves are horribly prickly, the pompom blue flowerheads justify the occasional painful brush with them.

Scotch thistle

Common name: Scotch thistle
Scientific name: Onopordum acanthium L.
Other scientific name/s:
Other common name/s: heraldic thistle

Plant status

Catchment management authority boundaries

Regionally prohibited in the North Central, Port Phillip and Western Port Catchments

Regionally controlled in the Glenelg Hopkins, Corangamite, Goulburn Broken, North East, West Gippsland and East Gippsland Catchments

Restricted in the Mallee and Wimmera Catchments

Read more about the classification of invasive plants in Victoria

Plant images

Plant biology

Appearance

Herbaceous plant – Forb (flowering herbaceous plant – not a grass)

Description

Scotch thistle is an erect annual or biennial herb growing to 2 m high and reproducing by seed and root pieces.

Stems

Scotch thistle generally has one main stem with numerous branches and broad spiny wings covered with dense woolly hairs, giving a whitish appearance.

Leaves

Leaf margins of Scotch thistle are cut or toothed, spiny and undulating. Dense, white woolly hairs grow on the undersides of leaves and are sometimes sparser on upper sides.

Rosette leaves are stalked and grow up to 40 cm

long. Stem leaves are smaller and without stalks, extending into wings along the stems.

Flowers

Scotch thistle florets are purple or mauve in heads surrounded by numerous spiny bracts (modified leaves at the base of flower). Heads are 2-6 cm in diameter, solitary or in groups towards the ends of the branches.

Bracts are woolly at the base and end in orange spines. Flowers are produced in late spring and summer.

Fruit No Fruit

Seeds

Seeds of Scotch thistle are 4-5 mm long, grey with dark mottling and are attached to a pappus (parachute) of toothed hairs or bristles up to twice as long as the seed.

The pappus is often detached from the seed in the head.

Growth and lifecycle

Method of reproduction and disperal

The major means of dispersal for the Scotch thistle is by seed, but it can also be spread from severed root pieces.

Rate of growth and spread

Scotch thistle seeds can germinate at any time of the year, hence infestations consist of plants of various ages and sizes. There are two main periods of germination; late summer-autumn and late winter-spring.

Seedbank propagule persistence

Scotch thistle is a prolific seeder and a single plant can produce more than 20,000 seeds.

Preferred habitat

Scotch thistle prefers subhumid temperate regions and grows well in soils of moderate to high fertility. The weed is competitive in annual rainfall areas of 500-850 mm. It does not grow well on waterlogged soils.

Growth calendar

The icons on the calendar below represent the times of year for flowering, seeding, germination, the dormancy period of Scotch thistle grass and also the optimum time for treatment.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Seeding
Germination
Dormancy
Treatment

Impact

Agricultural and economic impacts

Scotch thistle competes well with pasture resulting in pastures being overrun by this weed. It is not grazed by stock due to its dense spines. Animals rarely eat the plant.

Management

Prescribed measures for the control of noxious weeds

  • Application of a registered herbicide
  • Physical removal

Important information about prescribed measures for the control of noxious weeds

Other management techniques

Changes in land use practices and spread prevention may also support Scotch thistle management after implementing the prescribed measures above.

Parsons, W.T. and Cuthbertson, E.G. 2001, Noxious weeds of Australia, 2nd edn, Inkata Press, Melbourne & Sydney.

Department of Primary Industries, Scotch Thistle Regionally Prohibited Weed Fact Sheet February 2010

Globe Thistle (Echinops ritro)

Hardy, herbaceous perennial
Description: Spherical, metallic-blue flower heads in late summer; stiff, spiny, dark green leaves have downy undersides
Habit: Compact, clump-forming plants 2-4 feet high and 2-3 feet wide
Culture: Grows easily in any well-drained soil with full sun; tolerates dry conditions once established
Hardiness: Cold hardy to USDA Zone 3
Origin: Europe, Asia
Attributes: Attracts butterflies and bees, Cut flower, Rabbit resistant, Drought tolerant
Globe Thistle, a Mediterranean plant long in cultivation throughout Europe, is an undemanding perennial suitable for the border or the wild garden. Williamsburg’s John Custis might have received this species, or its more vigorous cousin, E. sphaerocephalus, from his English patron Peter Collinson in 1738. Both are listed in Parkinson’s early 17th-century herbal, and Philip Miller’s 18th-century botanical dictionary. Thomas Jefferson’s gardening mentor, Bernard McMahon, also included Small Globe Thistle in his 1806 American Gardener’s Calendar. Today it is popular as a cut flower and for drying, and the flowers attract butterflies.
Arrives in a 3.5″ pot.

The last post was about thistles, since I had been hard at work in the garden getting rid of as many as I possibly could manage, but there are lovely garden flowers that have thistle characteristics without their tendency to elbow everything else out.

Long ago, when planting my first garden on Glen Echo (isn’t that a lovely name for a street? Too bad it was located right next to a raucous, busy thoroughfare), I helped an elderly lady do some yard work. She grew a pretty perennial border and the globe thistle stood in a healthy stand within it. She called it “Goat’s thistle” as I recall, but its official name is Echinops. I think “goat’s” thistle is more of a noxious kind, and as a matter of fact, grazing goats are one means of getting rid of your thistle weed problems. Anyway, once I started my rural garden I decided that I had room for this plant with the steely blue flowers, and for another lovely thistly looking bloom, Eryngium.

Those were both planted in a part of the garden I sadly had to relinquish back to nature’s grasses, and the Eryngium succumbed to constant mowing, but the Globe thistle still survives. Surprisingly it never did spread into a large patch like I envisioned, but I like its odd flowers; they are reminiscent of a stiff Allium that comes along in midsummer.

I’m thinking of those flowers, now, since I would like to renew their acquaintance, and find a place to start them in my present flower gardens. They normally are quite persistent and tolerant of drought. Their subtle colors blend well into the garden and I think they would match up well with Russian sage and red Monardas. They might look pretty near the dusky ‘Diablo’ ninebarks (Physocarpus), if I have a space to tuck them in. I think I do! So that is an idea to jot down in my notebook.

It was E. maritinum that I grew, and while I might try Miss Willmott’s Ghost ( E. giganteum) the smaller “Sea Holly” has a cultivar called ‘Sapphire Blue’ that I’d like to look for at the end of summer.

Plant Families

Although Canadian thistle, Globe Thistle, and Eryngium all have a bristly appearance, only the two thistles are related inside the Asteracae family. The Sea Holly” is a different clan, completely: the Apiaceae. Yet, they have a similar appearance in the garden and their assets are much the same as well. Blue ( gray blue, actually) in flower, architectural in presence, of medium heights, and tough plants.


In these pictures the first one has Echinops with Adenophora and an orange daylily. The second picture has a stand of eryngium and coneflowers (Echinacea) just coming into bloom.

Plants For A Xeriscape

Both these plants like sunny spot, even sun baked. They handle drought and are beneficial plants for bees and butterflies, but not native to the USA. You can also dry the flower heads for arrangements.

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Globe Thistle Care: How To Grow Globe Thistle Plants

Thistles are one of life’s prickly jokes. They thrive almost everywhere and carry a nasty sting when they contact skin. However, they have an exciting shape and come in deep purple and blue hues that are irresistible additions to the perennial garden. Learn how to grow globe thistle perennials for season after season of appeal.

What is Globe Thistle?

Globe thistle (Echinops ritro) is in the Aster family. The large spiky flowers appear in early summer and last up to 8 weeks. They are perennials, so the plants will make long lasting garden companions with hardy habits and minimal globe thistle care. Globe thistle flowers are particular stand outs with blooms up to 2 inches across on 3 to 4 foot stems.

Echinops is the botanical name for globe thistle. They are stunning flowers with deep dark blue petals set in a spiky frame. The leaves are deeply notched, dark green on top and slightly silver underneath and

slightly hairy. The plants are native to Asia and Europe and the name means hedgehog in Greek, which is appropriately referencing the prickly blooms.

Glove thistle flowers make excellent dried displays and last for years as part of an everlasting flower display. Globe thistle echinops encompass over 120 species, only a few of which are in cultivation. Some common forms are bannaticus; the super spiny exaltatus; ritro, with its white foliage undersides; and sphaerocephalus, which has white to gray flowers. The plants are hardy to United States Department of Agriculture zones 3 to 8.

How to Grow Globe Thistle

Growing globe thistle from collected seeds is imprecise, but purchased cultivated seed has a better seedling rate. The plants also often self-seed. Growing globe thistle from clump division is the fastest way to get flowers. Divide the basal growth away in spring from plants that are at least 3 years old. You may also take 2- to 3-inch root cuttings in spring to start new plants.

Plant basal or root cuttings in loosened soil that is moderately acidic for best results. Water the young plants twice per week for a month and then gradually reduce supplemental watering as they establish.

Choose a well-drained site in full sun for the best growth, although they will tolerate partial shade.

Globe Thistle Care

These perennials are one of the easiest plants to maintain. They tolerate drought conditions once established and have few pest or disease problems.

Occasionally the heads will be too heavy and require staking. You can cut back the basal foliage to encourage re-bloom. If you do not want any reseeding problems, take off the flower heads after the color fades.

Globe thistle care is minimal and you will enjoy watching the bees sample the flower’s nectar.

If I got to rule for a day, I think I would put short fences into my first diktat. I am quite sure I wouldn’t like my neighbours half as much as I do if it weren’t for short fences. They allow for chance encounters, incidental chit-chat, the sort of thing that makes a neighbourhood. Also, I can enjoy their echinops while sitting in my own garden.

Echinops, the blue hedgehog thistle or globe thistle, is a perfect sphere of blue that appeals to every pollinator around. I counted three different bumblebees, four hoverflies and a honeybee as I said good morning (to them and the neighbours). There’s something very pleasing about a big, fat bumble stuck on a pincushion of a flower.

When not looking lovely in the garden, they look quite something in a vase, both in flower and afterwards, when you are left with a washed blue seedhead. They last a long time, too, particularly if you change the water often.

The species Echinops ritro is lovely if you have space to let it roam – in a wild or gravel garden, say – but it can be a bit much for smaller spaces, because it tends to self-seed rather a lot. Likewise, E. sphaerocephalus, with its large, blue-grey flowers and steely-grey foliage, is lovely as long as you don’t mind it seeding itself around. Still, you can often employ the local bird population to strip the seedheads, which keeps the weeding down. A better bet, maybe, is E. ritro ‘Veitch’s Blue’. It has purple-blue flowers, rarely self-seeds and grows almost anywhere, as long as there’s some sun. E. bannaticus ‘Taplow Blue’ is another that remains contained and easy to please. It is tall, at 1.2m, and will grow in sun or part-shade, in clay or gravel, and won’t topple over. The flowers are a stately grey-blue; it makes rather a good statement plant.

E. bannaticus ‘Blue Glow’ has perhaps the most intense of all blues, so is brilliant for flower arranging. It will self-seed, but that shouldn’t pose much of a prolem, because everyone coos over it.

The purple hues in the blue of echinops look great with pinks such as brook thistle Cirsium rivulare ‘Atropurpureum’ or among astrantias and echinaceas. Or go the other way and put them with yellows and oranges: among day lilies and achilleas, for instance. There’s a good Piet Oudolf trick whereby you pair the upright purple-blue towers of agastache among a drift of round echinops.

Echinops is tolerant of quite a wide range of soils, provided the top layer around the base of the plant drains well. I have seen it thrive on getting its feet deep into clay and do equally well in the thinnest of soils. My favourite thing after those lovely blue balls is that the slugs do little damage.

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