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Now is time to plant gray to enjoy in summer garden

English lavender grows to about 3 feet tall.
English lavender grows to about 3 feet tall.

Now is the time to choose and plant a bit of gray among the green so plants can get their roots established before winter becomes spring and summer is suddenly upon us. Once established, they seldom wilt and rarely show stress during the harshest Northern California summers, and manage to do so with very little water and care. There are gray-leaf plants for the front of the border, for the back of the border, for creeping along the ground, as well as shrubs and trees that can be planted as a focal point in the garden.

If you’ve never worked with gray foliage in the garden, start with tried-and-true performers: lavender, santolina and artemesias. Next time you’re at the nursery, take a potted gray foliage plant and put it next to other plants to see how it looks until you find a combination you love. Santolina comes in gray and green foliage, and the two look great together. The artemesias are generally silvery gray, so look best next to bright or dark green. Try combining it with a dark green ceanothus or some of the agapanthus with indigo-colored flowers.

With a few exceptions, gray-leaf plants are sun lovers, so make sure they get plenty of sunshine. Always group plants with similar needs: sun lovers with other sun lovers. Remember the rule of planting in odd numbers so the garden looks more natural than formal.

Plants, no matter how well suited to the climate, can only be as good as the soil in which they are planted. “Remember, what you don’t see under the ground – the root system – is as important as what you see above the ground,” said Carolyn Singer, author of “The Seasoned Gardener.” Singer adds plenty of organic matter to her soil. Her foothill soil is deficient in phosphorus, so she adds bone meal each time she plants. “Never, never forget a good layer of mulch,” she added.

Good drainage is also important. Summer water is usually no problem as long as it isn’t excessive since most gray-leaf sun-lovers dislike wet feet, Singer explained. Planting them on a slope ensures they won’t have wet feet in the winter.

Here are some of my favorites:

Cottage pinks

The small, spiky leaves of old-fashioned cottage pinks are silvery-blue. During early spring, the plants send up slender stems topped with clove-scented blossoms. In shades of pink and white, the flowers fill the air with their heavenly fragrance and attract butterflies by the dozen.

Part of the genus Dianthus, old-fashioned pinks are cousins to carnations and Sweet Williams. They are hardy – even tough – mat forming plants that demand a place along the front of the border. The silver-gray foliage can also soften plantings of shrubs or perennials, act as a transition between borders or stand on its own as an accent. They’re popular planted beneath roses.

The names of the old-fashioned pinks are as evocative as their fragrances: Pheasant’s Eye, London Lovely, Dainty Dame, Allspice, Bat’s Double Red, among others. Many were grown in cottage gardens in the 1800s. There are also pinks that form tight little cushions of green or silver-blue foliage and include varieties like Tiny Rubies and Blue Hills.

The best of the lot for foliage and flowers in a mixed border are D. ‘Inchmery’ and D. ‘Rose Du Mai.’ Both maintain their good looks the entire year without becoming straggly or sparse. D. Inchmery has pale, shell pink flowers. It dates back to the 1700s and is one of the most popular pinks. D. Rose Du Mai has deeper, though still pale, pink flowers. I have it circling a cherry tree that stands alone in a pathway.

Some pinks are short lived; others tend to sprawl. Dianthus aficionados don’t seem to mind and like to collect them all if just to grow a bit of history. D. ‘Mrs. Sinkins’ dates back to an 1868 garden in Slough, England. Named by English gardener John Sinkins, it remains one of the most popular – and most fragrant – of the cottage pinks.

Like many cottage garden plants, these thrive on neglect. Give them sunshine, good drainage but not too much water. Trim the flowers back after blooming. Keep them near the front edge of the border since more aggressive perennials and shrubs can overrun and smother them. You want to be able to walk by and enjoy their fragrance.

Lavender

Lavender is undeniably the most popularly planted gray-foliage plant. Who could resist its heavenly, heady scented leaves and stunning purple flowers? Give it plenty of sunshine, well-drained soil and minimal water and it will flourish. Plant a hillside of lavender, scatter it throughout the garden, plant it among the roses or use it as a hedge. Shear it back after it blooms (except Spanish lavender) and it will last for years, although it will eventually get so woody it will need to be replaced.

Lavandula angustifolia is the familiar and always popular English lavender. Its flowers are deep violet, the foliage gray and spiky. It grows to about 3 feet tall. L. dentata is the French lavender. Its foliage is greener and quite ferny and soft to the touch. French lavender blooms almost continuously. L. stoechas is Spanish lavender. It tends to sprawl, dislikes being cut back, but produces spikes of fat, showy, purple flowers.

There are dozens more types of lavender on the scene these days, and local nurseries carry many of them. Foliage comes even whiter, flower stems longer, bloom time has been extended, all the while preserving lavender’s carefree, drought-tolerant, sun-loving nature. Find one you love and plant several in the garden.

Rockrose

Most gardeners discover rockroses while driving down the freeway. Suddenly one spring morning those hardly noticeable gray-green shrubs growing along freeway ramps and medians are covered in bright pink or white crepe paperlike flowers. Later that evening when you drive by again on your way home, the flower petals will be lying on the ground at the base of the shrub. But next morning, the plant will be again covered with flowers. The process repeats itself every day for about a month.

You’ve discovered the wonderful, amazing, carefree rockrose, which comprise the genus Cistus. The genus contains about 20 small to medium, sometimes aromatic shrubs. Some make low mounds while others hug the ground or grow to six feet tall. Foliage ranges from dark green to gray green.

They are happiest growing in harsh conditions – not too much water or pampering after they are established. You will need to cut them back about a third each year to keep them from getting woody, and may need to replace them after a few years, because no matter how hard you try, the bushier, taller varieties will eventually get woody in the middle of the plant. They are easily started from cuttings. The low growing ones, especially the ground hugging ones, can be part of a fire resistant planting, and take less maintenance as far as pruning.

Varieties to look for: I love them all, but look for Cistus ‘Sunset,’ (hot pink flowers, gray green leaves), C. salvifolius (sage-leaf rockrose, ground hugging), and C. ‘Warley Rose’ (cerise colored flowers, grows to four feet tall). C. ladanifer, also called crimson-spot rockrose, is best known for its smooth, sticky – albeit dark green – leaves. It produces a gumlike resin, believed to be the source of biblical ladanum.

Agave

Mention agaves, and most people think of the huge century plants with sharp, stiff spines that are eye-level for children. Then there’s the towering spire of flowers if you’re lucky, although the plant dies soon afterward and you’ve got this huge mess to clean out of the garden.

Things have changed. Today’s agaves are all about smaller spaces, and come in a variety of small garden-friendly shapes and sizes. These smaller agaves are easier to manage than the old-fashioned century plant.

All form rosettes of succulent-type leaves. If they flower, the stalk rises up from the center of the plant, and often that part of the plant dies once flowers are spent. However, the plant sets offshoots, called pups, alongside the mother plant before it dies, so you never really lose the plant. The agaves originated in the American Southwest and in Mexico. They range in color from powder blue to steel gray to silvery white. Many of the new cultivars still have wicked-looking spines, but since the plants are much smaller than the century plant, they are less threatening and easier to incorporate into a mixed planting.

The artichoke agave has a definite blue tint, and the spines and edges are orange, a stunning combination. Another favorite is A. parryi. It grows slowly to 3 feet by 3 feet, and in the right conditions, will send up a flowering stalk as high as 10 feet. The buds are pink, then open to reveal greenish yellow flowers. A. ‘Blue Flame’ is a smaller grower and comes by its name honestly. Each succulent “leaf” looks like a slim blue flame. One of the larger agaves is called Whale Tongue, and it lives up to its name, although it is a slow grower.

Give agaves plenty of sun and good drainage. Even though they are shallow-rooted, they need little water. Stop watering them late fall so they go into winter on the dry side. In the wild, agaves will shrivel and look almost dead during severe droughts but bounce back when watered again. They do well in pots.

Wormwood

Wormwood is an ignoble name for such a stunning plant. Officially called artemisias, their brilliant silver, fernlike foliage seems to shine. It always looks fresh, and the plant gives the garden a light and airy feeling. It blends well with deep green foliage, boldly colored flowers, almost anything. Unfortunately, the flowers are a disappointment. The flower stalks are floppy and thin. I cut the flowering stalks away before they have a chance to open. Hybridizers have developed artemisias that never or rarely bloom.

Give artemisias plenty of sun, even poor soil. Just don’t give them a lot of water. They look best grown on the hard side, like herbs.

The genus Artemisia is a large one with more than 200 species. Some are evergreen (actually ever gray), some deciduous, and some make woody shrubs. They are mainly native to the Mediterranean and the Caucasus Mountains in Turkey, but there is a California native that hails from the Channel Islands called A. californica.

One of the most popular is A. ‘Powis Castle,’ which mounds to about 3 feet tall and 6 feet across. However, with ample water, its stems root as they go, and a single plant can cover 20 or 30 feet in a couple of seasons. There is also one called A. ‘Silver Mound’ that makes a small silvery gray mound.

To keep them from getting woody, I cut them back by half each fall. They seem to bounce right back no matter how severely they are pruned.

Dichondra ‘Silver Falls’

I first spotted Dichondra ‘Silver Falls’ from across two aisles at the nursery. Its silvery foliage lured me over, and I was not disappointed. This plant has it all: beautiful leaves, vigorous grower, heat and drought tolerant, deer resistant, performs well in the ground or in pots.

The shimmering, pewter-colored, fan-shaped foliage – each leaf a scant three-fourths inch – was stunning. The long stems trailing down the sides proclaimed immediately this was a plant perfect for a hanging basket, a retaining wall or for carpeting the ground among other perennials and shrubs. Stems can trail several feet.

Also called silver ponyfoot and silver nickel vine, it is hardy to USDA Zone 8, so can take some cold along with the heat. Give it sun or part shade, though it preforms best in full sun. It is native to southeastern Arizona and Mexico. The densely packed, tiny hairs on the surface of the leaves give it a metallic sheen. It is part of the morning glory family. It looks great paired with geraniums or lantana. Or try it in a basket with brightly colored coleus, or purple and pink petunias. For a cooler look, plant it with white petunias.

It’s easy to propagate since it can root as it travels across the soil. You’ll definitely want to share this one with friends.

Dusty miller

There are several gray-leaf plants commonly called dusty miller. Some are used as bedding plants alongside colorful annuals, while others are stalwarts in the mixed border. They all have startlingly beautiful silver gray foliage, soft velvety leaves and are tough customers when it comes to heat, sunshine and drought. I’d wager dusty miller is one of the most popular gray-leaf plants for Northern California gardeners.

Some belong to the genus Senecio, while others are part of the genus Centaurea. There are a few that you’ll see labeled either way, so it’s a bit of a botanical nightmare. Experts estimate there are about 500 plants in the dusty miller family. This is one of those few times when the common name is all a gardener needs to know!

Generally, the common bedding plant sold in six-packs at nurseries and garden stores is the Senecio cinaria. They grow up to about 18 inches tall, and can be easily tucked among other shrubs and perennials in the garden and then left to their own devices. They are tough survivors of many conditions, although they can be killed by overwatering faster than too little water.

There’s another dusty miller, a bit larger and with finely textured fernlike leaves, Centaurea cineraria. The most stunning cultivar is called Colchester White. Its leaves are deeply cut and the foliage is silver white.

Best way to choose a dusty miller: Find foliage you love and buy at least three for the garden.

Sea holly

I was taking photographs in the Storer Garden at the UCD Arboretum when I stumbled upon sea holly (Eryngium amesthystinum). The thistlelike foliage is deeply serrated, as though someone had taken a pair of snips and cut a beautiful pattern into the leaves. Blue-tinted silvery bracts surround each brilliant blue flower. The combination of white gray foliage tinged with deep steel blue is stunning.

It’s a must-have for the dry garden. They have deep, carrot-like taproots, stiff stems and a rosette of foliage. They generally grow 1 to 3 feet tall, although some cultivars can grow as tall as 6 feet. The steel blue flowers last a long time.

The biennial form, E. giganteum, is fondly known as “Miss Wilmott’s Ghost.” That isn’t a cultivar name, but is based on the story that Ellen Wilmott, a well-known 1900s English gardener, was fond of dropping seeds of the plant in gardens where she did not see plants already growing. Seedlings would appear the following year, grow and bloom without the gardener first realizing how the plants got there. Then they’d remember Miss Wilmott’s visit.

English garden author Beth Chatto calls sea holly “one of the loveliest things in the dry garden on dusty days.”

Spurge

Neither deer nor drought will harm the spurges, guaranteed.

However, this Mediterranean native comes with a warning: If you break a leaf or cut the stems, you’ll see a white sap ooze from the cut. Avoid getting it on your skin, and if you do, rinse the area with cool water. Don’t touch your eyes with sap on your fingers, either. You can cut stems to use in flower arrangements, but dip the cut edge in boiling water to keep sap from bleeding out.

Warning aside, it’s a wonderful, stately – and wildly popular – plant for the low-water, low-maintenance landscape. Spurge is part of the genus Euphorbia. It is a large genus with about 2,000 species, including succulent, cactuslike types as well as upright and prostrate perennials and shrubs. Poinsettias are part of the group, too.

You’ll find the bright, electric yellow flowers at the tips of the stems along with cupped lime green bracts that surround dark purple or black nectar glands. When ripe, the plant shoots the seeds out of the pod, and many of the seeds land several feet away. The leaves are arranged opposite each other along fleshy stems, and are usually blue green or gray green in color, although some cultivars come in shades from dark green to reddish green. Depending on the cultivar, the plant can be ground hugging or grow to 3 or more feet tall. Plants need to be cut back each fall – wear gloves – but come back from the roots the following spring.

Most nurseries carry several varieties of spurge. E. amygdaloides ‘Purpurea’ sports showy purple foliage and purple flowers, and is attractive many months of the year. The best blue-leaved sorts include donkey tail spurge, E. myrsinites, which creeps along the ground, and E. ‘Blue Haze,’ with reddish stems and dusty blue foliage.

South African geranium

The slightly aromatic, downy leaves of the creeping pelargonium, commonly called the South African geranium, stay close to the ground. The stems insinuate themselves among other plants, providing a gray carpet beneath. Then suddenly one summer day the plant bursts into bloom with the brightest wine-colored blooms around. What a contrast to the foliage. The flowers last quite a while, and finally the stems fall against the ground. Leave them be, and they will root and off the plant will go. It is not, however, a thug that needs to be controlled. Any unwanted plants can be pulled away easily.

Pelargonium sidoides is native to parts of South Africa and the southeastern cape. It is quite drought-tolerant. Grow it in the ground or in pots.

In its native habitat, the plant is mainly used for medicinal purposes. It has been collected so widely that it is hard to find in the wild. In fact, if you search P. sidoides online, you’ll find more websites dedicated to its alleged medicinal uses than ones that talk about its uses in the ornamental garden.

Lavender cotton

The gray-foliage lavender cotton (sold as Santolina incanus and Santolina chamaecyparissis) stands unscathed by anything Mother Nature can muster during a California summer. No amount of blazing heat, sunshine or dry weather bothers this tough, yet beautiful shrub. Plus, it is dependably deer-resistant.

Rub your hand across the foliage to release its fresh, clean scent. Look closely at the foliage: Each silvery-white “leaf” resembles a tiny serrated comb. This Mediterranean native, which is part of the aster family, grows about 2 feet tall and spreads to 3 feet wide. And when you think the weather can’t get any hotter, the plant sends up short stems topped with bright yellow, three-fourths-inch wide, button-type flowers. It makes a very cheerful picture.

Santolina grows in poor soils, in full sun, and with very little water, even when newly planted. It makes a tight mound, is easily started from cuttings, and can be clipped back if the growth gets too lanky. In fact, gray Santolina and its green-leaf cousin are often used in English knot gardens, which are cut into tight hedges.

It’s commonly called lavender cotton, petite cypress, ground cypress and holy herb, although it has nothing to do with lavender, cotton or cypress. Nor is it a culinary herb. In ancient time it was used to repel moths.

Santolina cultivars blend well with rosemary, rockroses, catmint and salvias, as well as low-growing types of ceanothus and manzanita. An annual trim after the plant has bloomed will keep it neat and tidy for many years.

Succulents

Everyone loves the old-fashioned succulents called hens and chicks. Since both the Echevarias and the Sempervivums are commonly called hens and chicks, it can be a bit confusing.

Both are perfect for carpeting the ground beneath other shrubs or cascading down the sides of a pot. They don’t mind dry spells, but appreciate an occasional watering to look fresh and plump.

Leaves around the base of the plant tend to die off and look unsightly, so remove them once they have dried. They will need more water if grown in full sun, and may be susceptible to sunburn.

They produce a long flowering stem – 8 or more inches long. The tiny flowers are yellow or orange. Hummingbirds love them.

Lamb’s ears

No one can pass by a clump of lamb’s ears without touching them. The plant carpets the ground with leaves that are soft and velvety. It’s a great plant to use to introduce children to gardening: They will love to rub its furry leaves.

Beneath that furry exterior, however, lies a plant that is tough as nails, a survivor in any garden situation. Give it sun, poor soil and drought conditions, and it will still thrive.

In early summer it sends up a 2-foot-tall fuzzy stalk covered with pale lavender flowers. The plants get a bit leggy after they bloom, so most gardeners pull away the flowering stalks.

There are cultivars, including one called S. ‘Silver Carpet,’ available that don’t bloom.

Jerusalem sage

Jerusalem sage (Phlomis fruticosa) is a stately plant that grows upwards of 3 feet tall and spreads its woody branches as wide as 6 feet. The plant is well worth growing, even though it takes up a lot of real estate. Come summer, it sends up flower stems that tower above the foliage. Each stems has several whorls of yellow, hooded flowers. Once the flowers fall away, the seedpods make interesting dried arrangements.

The feltlike leaves are gray green, with whitish undersides. The tips of the leaves are pointed and hang down slightly. Plants like full sun and occasional water, although they will thrive in a mixed border alongside dahlias and other plants that demand more regular watering.

P. lanata is smaller, just 2 feet tall and 3 feet across. The plant is found in dry rocky places throughout the Mediterranean. Give it full sun, and occasional water once established. The deer leave this one alone. Other than cutting away the old flowering stems, it doesn’t need much pruning.

All Phlomis varieties look great planted with ornamental grasses. They also mix well with the tall purple flowering stems of Verbena bonariensis.

Culinary sage

Salvia officinalis, also known as culinary sage, may be the go-to plant in the kitchen, but I have it planted among the perennials and shrubs because it is a beautiful plant in the ornamental garden.

It is a tough plant that can survive many garden situations. It always looks good. I love it planted next to plants with dark green foliage, and when I need sage for the kitchen, I can cut all I need without the plant ever looking pruned. The leaves are a beautiful gray color, a bit rough to the touch. It also comes with purple-tinged foliage, another tough stunner in the garden.

One of the showiest of the salvias is S. officinalis ‘Berggarten.’ Its soft foliage is stunningly silver blue. It’s also a tough-as-nails perennial for the garden.

Another salvia with downy foliage is the clary sage, Salvia argentea. It’s a biennial, which means it blooms its second year, then dies, but worth a place in the garden.

Red yucca

The red yucca (Hesperaloe parviflora) isn’t related to the yucca at all; it is more closely related to the succulent aloes. It has stiff, strappy foliage like a yucca, except plumper and rounder, and each grasslike leaf has curling threads along the edges.

The plants send up long, arching flowering stalks midsummer. They bloom from the bottom up, and amazingly, there are still flowers blooming in October. They attract hummingbirds. Once the flowers are finished, the plant makes fat, round seedpods that also look interesting.

Hesperaloe is native to Texas and New Mexico. Give it plenty of sun, good drainage and go easy on the water. Give them a deep soaking twice a month. It also does well in pots but will need to be watered more regularly. All you really have to do is cut away the old flower stalks.

Russian sage

Russian sage is an upright grower – its delicate silvery gray spires get to be 3 feet tall and are covered in tiny blue flowers. They bloom late in the season, so they are perfect for extending the flowering season from late summer into early fall.

They die back November or December, but I don’t cut them to the ground until spring when I see the new growth peeking out from the ground. The clumps get larger each year.

Luckily for gardeners in deer country, this is a plant they leave alone, perhaps because the tiny leaves are aromatic. Give it plenty of sun, well-drained soil and a weekly watering once established. I have it planted among the old-fashioned red hot pokers (Kniphofia sp.) and the bright green kniphofia blades contrast beautifully with the silvery gray Russian sage foliage.

Yarrow

With about 85 species from which to choose, there is a yarrow for every garden: low, creeping varieties that cover the ground, clumping sorts that send up tall flowering stalks.

They all have deeply divided, fernlike foliage, which ranges from deep green to gray green to silvery gray. The grayer foliage types are more sun-loving and drought-resistant than the green-leaf varieties. The flowers are large, flattened, tightly packed clusters.

No matter the growth habit, the foliage is similar for all cultivars. Cut them back after bloom and the plant will produce another crop of flowers. The plant will continue blooming sporadically through November. The big yellow types of yarrow keep their color for a long time and are great in dried arrangements. Cut them while the flowers are still yellow and hang them upside down to dry so stems stay straight.

Yarrows thrive in most soils, don’t mind full sun, and take little to moderate water.

When plants get crowded, dig them up and divide them. They aren’t deeply rooted, so it’s an easy project. My favorites: A. Coronation Gold and A. Moonshine. Both produce tall, stiff stems with large yellow flowers. Moonshine is lighter in color.

Iris

Bearded irises are rugged and reliable. They survive neglect, drought and poor soil. The flower colors are magnificent, the combinations stunning, and the scent of the flowers perfumes the air like no other flower. It’s no wonder the genus was named for the Greek goddess of the rainbow.

The genus Iris contains more than 300 species. Almost all grow from rhizomes, which resemble a misshapen potato. Iris flowers have three upper petals called standards, and three lower petals called falls. Bearded irises (I. germanica) are easily identified by a thick, hairy tuft, or “beard,” on each of the falls. They’re native to central and southern Europe, and many people call them German bearded irises. They range in size from miniatures that hardly top 8 inches to ones that exceed 4 feet tall in bloom.

Hybridizers have created bearded irises of almost every color, from deepest indigo to bright orange, pale yellow, warm peach, startling white and reddish purple as well as stunning color combinations. There are probably 100,000 named varieties of bearded irises.

They mix well with perennials and shrubs like lavender, daylilies, poppies, daisies and roses. The spiky foliage is a beautiful soft green color, and a shape that blends well with other plants. The newer reblooming varieties produce flowers throughout the year, even into December.

Overwatering kills more iris than disease or pests.

PLANT LIST

Here are a few more to try, but you’ll likely find many, many other wonderful plants in shades of gray.

Trees

Silver Korean Fir (Abies koreana “Horstmann’s Silberlocke”)

Cedrus atlantica “Glauca”

Smooth Arizona cypress (Cupressus arizonica glabra)

Silver Dollar Gum (Eucalyptus cinerra)

Colorado Blue Spruce Fat Albert (Picea pungens var glauca “Fat Albert”)

Silver Pear (Pyrus salicifolia)

Perennials

Yarrow (Achillea sp.)

Alyssum (Alyssum saxatilis)

Pearly Everlasting (Anaphalis margarita)

African Daisy (Arctoctis fastiuosa or Venidum fastuosum)

Wormwood (Artemesia sp.)

False Dittany (Ballota pseudodictamnus)

Cottage pinks (Dianthus sp.)

Silver ponyfoot (Dichondra argentea)

Glove thistle (Echinops ritro)

Sea holly (Eryngium giganteum “Miss Willmott’s Ghost”)

Spurge (Euphorbia myrsinites, E. characius)

Lavender (Lavandula angustifoila, L. stoechas)

Rose Campion (Lychnis coronaria)

Horehound (Marrubium incanum)

Catmint (Nepeta sp.)

Russian Sage (Perovskia atriplicifolia)

Rue (Ruta graveolens)

Sag (Salvia officinalis S. clevelandii , S. argentea, S. o. “Berggarten”)

Dusty Miller (Senecio sp.)

Lamb’s ears (Stachys byzantina, S. lanata)

Mullein (Verbascum bombyciferum)

Adam’s Needle (Yucca sp.)

Wormwood (Artemesia canescens, A. ludoviciana “Powis Castle”)

Silver Nickel Vine (Dichondra “Silver Falls”)

Dittany of Crete (Origanum dictamnus)

South African Geranium (Pelargonium sidoides)

Shrubs

Rockrose (Cistus sp.)

Sun rose (Helianthemum mummularium)

Lavender Cotton (Santolina incanus S. chamaecyparissus)

Butterfly Bush (Buddleia alternifolia)

Succulents

Agave sp.

Echeveria sp.

Sempervivum sp.

Grasses

Fescue (Festuca glauca)

Blue oat grass (Helictotrichon sempervirens)

Japanese Silver Grass (Miscanthus sinensis)

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