Maritime Northeast

• 25 Suggested Easy Rock Garden Plants
• 25 Easy ‘Choice’ Rock Garden Plants

25 Suggested Easy Rock Garden Plants

Antennaria dioica ‘Rubra’

Pink pussy-toes forms a flat, silvery, evergreen mat which is appealing all year. In early summer, plants produce upright stems 10-15 cm, topped with a tight cluster of pink flowers. Prompt removal of faded flower will maintain tight growth. This species is very drought tolerant.

Arabis caucasica

Rockcress forms a loose mat with grey-green foliage and 15-25 cm sprays of white or pink, four-petaled flowers in spring. Provide full sun and trim faded flowers to keep plants more compact.

Armeria maritima

Sea thrift is an evergreen mounding plant with narrow, almost grass-like foliage. In late spring-early summer, they produces wiry stems topped with a rounded cluster of pink or white flowers. Removal of the faded flowers will often encourage sporadic blooms all summer.

Artemisia schmidtiana ‘Silver Mound’

Silver Mound wormwood is a semi-woody shrub-like plant grown as a foliage accent. It produces a rounded mound of lacy, soft, silvery foliage on plants reaching 20-30 cm. The foliage is fragrant when bruised. Flowers are produced in mid-summer but are also silvery so not particularly noticeable. Plants are very drought tolerant.

Aster dumosus

Dwarf michaelmas daisy helps to extend interest in the rock garden through its late summer-through fall blossoms. There are numerous cultivars with white, pink, red to blue flowers. The most compact forms will form mounding plants 20-30 cm.

Aubrieta deltoidea

Wallcress forms a low, trailing mat with grey-green foliage and short 15 cm sprays of pink, purple or purple-blue four-petaled flowers in spring. Provide full sun and trim faded flowers to keep plants more compact.

Aurinia saxatilis

Perennial alyssum forms a low, somewhat mounding plant with fuzzy grey-green foliage. In late spring, plants produce 20-30 cm stems topped with clusters of small, bright yellow, four-petaled flowers. Trim faded flowers to maintain more bushy plants.

Campanula carpatica

Carpathian bellflower forms a mounding plant 20-30 cm. In early summer, plants produce masses of outward to upward-facing blue or white bells. Deadheading will extend the blooming season and help curb the spread of seedlings.

Campanula poscharskyana

Serbian bellflower is a vigorous, mounding plant with somewhat trailing flower stems that may reach 15-20 cm. Plants produce mid-blue star-like flowers, but cultivars are available in white and lilac-pink. Flowers are produced ‘en masse’ in early summer but prompt deadheading will often result in a second flush of blooms later in the season.

Dianthus deltoides

Maiden pinks produce evergreen mats of light to deep green foliage. They sometimes adopt a purple tint in the colder months. In early summer, 15-25 cm wiry stems end in a loose cluster of white to magenta-pink flowers. There are many named selections. Deadhead faded flowers to keep the plants neater and help curb the spread of seedlings.

Dianthus plumarius

Cottage pinks are quite variable in size. Newer hybrids are preferred as they stay smaller and neater. As plants, they will form evergreen mats of blue-grey to grey-green foliage. In early summer, plants produce stiff stems 10-30 cm topped with a few relatively large, fragrant white to pink flowers. There are many named selections with the most compact forms having a dose of D. gratianopolitinus genes to help keep them small. Double forms also exist. Deadheading plants will help keep them more compact.

Genista pilosa ‘Vancouver Gold’

This creeping broom forms a low, trailing evergreen shrub which hugs the ground and cascades over rocks and walls. In early summer, plants are smothered in numerous yellow pea-like flowers.

Gentiana septemfida

Summer gentian is a herbaceous perennial with trailing stems. Plants form busy mounds to 20 cm. In mid to late summer, plants produce terminal clusters of royal blue, somewhat star-shaped flowers. This species prefers evenly moist soil and a little shade from hot afternoon sun.

Geranium sanguineum

Bloody cranesbill is a vigorous plant with somewhat trailing stems. Plants may reach 40 cm. They can smother nearby neighbors so give them space. Throughout the summer, plants will produce white or pink, saucer-like flowers which are about 4 cm in diameter.

Gypsophila repens

Creeping baby’s-breath forms semi-evergreen trailing mats which are covered in small clusters of fragrant, white or pink flowers in late spring-early summer. Trimming faded flower stems will maintain neater plants and help curb the spread of seedlings.

Iberis sempervirens

Perennial candytuft forms a low, spreading, evergreen sub-shrub 20-25 cm in height. In spring, plants produce billowing masses of white flowers. Trim faded flowers to keep plants compact.

Phlox subulata

Moss phlox forms trailing, evergreen mats of narrow, needle-like foliage. In early summer, plants are covered in nearly stemless clusters of white, pink to purple-blue flowers, often with darker central eyes. There are numerous cultivars available. Phlox douglasii is similar but a little smaller in stature. It is equally desirable.

Potentilla neumanniana

Spring cinquefoil is a low (5-10 cm), mounding alpine with semi-evergreen foliage. In late spring, plants produce prostrate, wiry stems studded with numerous five-petaled bright yellow flowers.

Primula auricula

The auricula primroses are just one of several groups of primroses that do well in our region. Auricula primroses form mounds of semi-evergreen tongue-like leaves. The leaves are often covered in white farina (powder-like substance). In spring, plants produce 15-20 cm stems topped with a cluster of flowers that come in a wide range of colours including green and brown!

Pulsatilla vulgaris

Pasqueflower is the harbinger of spring in our region with blooms beginning in April. Plants form tufts of hairy, carrot-like leaves. The flower stems arise 10-20 cm and are topped with single, large, cup-like flowers in white, pink, purple or red. The center of the flower is filled with many yellow stamens. Semi-double forms, like ‘Papageno’, also exist. After flowers fade, the stems elongate up to 30-45 cm and produce long-plumed seeds in a feathery head.

Saponaria ocymoides

Soapwort forms a semi-evergreen, trailing mat. In late spring, plants produce masses of pink flowers with conspicuously sticky buds. Trim faded flowers after blooming to maintain denser plants and help curb the spread of seedlings.

Saxifraga paniculata

Encrusted saxifrage produces silvery, evergreen rosettes that slowly spread to form a significant patch. Their foliage lends them year-long attraction. In early summer, stiff flower stems arise 10-15 cm and terminate in a rounded cluster of white flowers that often exhibit fine red spotting. Pale pink and pale yellow selections also exist, along with a multitude of hybrids.

Sedum spurium

Dragon’s-blood stonecrop produces somewhat trailing stems that root as they spread across the soil surface. Their semi-evergreen leaves are rounded and succulent. Leaf colour can vary from green to red and even variegated. In early summer, plants produce stems, up to 15 cm in height, topped with a flattened cluster of numerous star-like flowers in shades of pink, or less commonly white. Deadheading will maintain ‘cleaner’ plants. Sedum kamtschaticum is similar in habit but has green or variegated foliage with yellow flowers.

Sempervivum species/cultivars

Hens and chicks are one of the few ‘desert-like’ plants we can successfully grow in our region. Plants produce low succulent rosettes and increase by producing stolons that end in new rosettes. There are numerous species and hybrids to choose from, varying in the size, colour and hairiness of the rosettes. All eventually produce a stiff stem topped with a somewhat flattened head of numerous star-like flowers, mostly in shades of pink. Some Sempervivum are very tiny and hairy, such as S. arachnoideum, while others, such as S. tectorum, may produce rosettes up to 15 cm across. Their evergreen nature lend them year-round attraction.

Thymus serpyllum

Creeping thyme is perhaps the lowest rock garden subject for our region, with plants rarely exceeding 5 cm. They produce trailing stems with tiny leaves which are fragrant when bruised. Numerous selections are available with flowers in white, pink and lilac shades. They flower in early summer but often bloom sporadically all season. They are ideal for growing between flagstone walkways or the tightest chinks in the rockery. Thymus pseudolanuginosus (wooly thyme) is slightly larger with fuzzy, gray-green foliage. It is equally attractive.

25 Easy ‘Choice’ Rock Garden Plants

This is a list of more refined yet easy alpines you may choose from in our region. These species may not be easy to find at local nurseries, however, mail-order and seed sources (NARGS seed exchange) are available.

Androsace sarmentosa

Also known as A. primuloides, this little gem forms a small evergreen rosette from which arises, in late spring, a single stem 5-10 cm. topped with a cluster of pink, dark-eyed flowers. Plants spread by strawberry-like stolons to eventually form a solid mat. This species needs evenly mist soil with some humus.

Aquilegia flabellata

The best forms of this dwarf columbine form 10-15 cm mounds of divided blue-gray to gray-green foliage. In late spring, stiff stems produce a few, large blue and white bi-colored flowers held just above the foliage. White and pink forms also exist. They can self-seed but deadheading will curb this habit.

Armeria caespitosa

This thrift is more compact than A. maritima. Plants round a relatively hard dome studded in late spring with 5-10 cm stems which are topped with a tight round cluster of light pink or white flowers. Removal of the spent flowers will often result in sporadic re-blooming. Perfect for a larger trough.

Campanula dasyantha

Also known as C. pilosa, this alpine forms a running mat of glossy, light green foliage which is peppered with nearly stemless, relatively large blue bells in early summer. The flowers are fringed in hairs and have a paler ice-blue throat. Deadheading can result in sporadic blooms later in the season. Excellent trough specimen.

Dianthus gratianopolitanus

Cheddar pinks form low mats of evergreen, blue-green to gray-green foliage. In late spring-early summer, plants produce numerous thin stems 5-10 cm topped with a single, clove-scented pink blossom. There are many named selections available in pink shades. Deadheading after blooming will keep plants ‘clean’ for the rest of the season. Very similar is D. freynii.

Draba aizoides

This small Draba forms a rounded, evergreen tuft with stiff, spiky foliage. In mid-spring arise thin stems 5 cm. topped with a cluster of yellow, four-petaled flowers. There are several Draba which do well in our area but this species is perhaps the most reliable. Allow it to self-seed as plants are naturally short-lived. This one is ideal for troughs.

Dryas octopetala

White mountain avens forms a flat, evergreen mat. In early summer, 5-10 cm stems arise producing a single creamy-white, saucer-like bloom. These flowers often follow the sun, turning from east to west. After flowers fade, they develop feathery heads of silky-plumed seeds, reminiscent of small pasqueflower seedheads.

Gentiana acaulis

Few alpines are as impressive as trumpet gentians. Plants form evergreen, flat mats that are studded with large, nearly stemless deep blue trumpets in late spring-early summer. Equally as desirable is the similar G. angustifolia.

Gentiana sino-ornata

At the other end of the blooming season are the fall-flowering gentians. This species forms trailing stems 15-25 cm in length, terminating in a few large bright blue trumpets in October and into November. This species requires acidic soil that is high in organic matter. The hybrid ‘Kingfisher’ is equally desirable.

Geranium subcaulescens

This cranesbill forms a tufted mound to 15 cm. The flower stems are trailing and may reach 20 cm. From late spring-early summer and scattered throughout the summer, plants produce 2-3 cm saucer-like flowers that are magenta-purple with a nearly black eye. Somewhat similar is G. cinereum.

Hypericum olympicum

This dwarf St. John’s-wort is a mounding plant 15-25 cm. The foliage is an attractive gray-green. The stiff stems end in a solitary, relatively large, yellow five-petaled flower. The stamens extend well beyond the petals, imparting a star-burst effect. They flower in early summer and sporadically later on.

Incarvillea mairei

This tufted alpine is sure to draw attention. From a tuberous root, arises coarse, fern-like foliage and upright stems to 20 cm with loose clusters of large, pink, gloxinia-like flowers in early summer.

Iris hookeri

This dwarf iris is endemic to our region. It is sometimes sold as Iris setosa ssp. canadensis. Plants produce a clump of grass-like leaves 10-20 cm. In early summer, arise stems 15-25 cm, topped with a few large porcelain-blue flowers.

Leontopodium alpinum

The quintessential edelweiss is a standard among alpine gardens. This species forms a tuft of white-wooly foliage. In early summer arise stems 15-20 cm topped by a cluster of fuzzy white ‘daisies’ that last for several weeks.

Penstemon cardwellii

This beardtongue forms an evergreen sub-shrub with somewhat trailing stems that may root as they grow along the soil surface. In early summer, flowers stems, to 20 cm, form loose clusters of purple-pink, tubular flowers. Similar in appearance and equally desirable are P. fruticosus, P. rupicola and P. davidsonii.

Potentilla villosa

This semi-evergreen cinquefoil is wonderful year-round due to its silvery-silky trifoliate leaves. In late spring, this tufted plant stems up stems to 10 cm, which produce loose clusters of yellow, saucer-shaped flowers with a distinctive orange eye. They are apt to self-seed unless you promptly remove the faded flowers. A lovely specimen for a trough.

Primula marginata

There are a host of European alpine Primula which are ideal for our region…P. pedemontana, P. hirsuta, P. glaucescens to name a few. One of the most attractive is Primula marginata. This species forms a tuft of toothed, gray-green leaves heavily covered in white farina (powder). In mid-spring arise stems 5-10 cm topped with a loose cluster of fragrant purple-blue flowers. It’s a choice plant for a crevice or alpine trough.

Pulsatilla alpina ssp. apiifolia

Perhaps a little large for a small rockery, this imposing pasqueflower is among the most impressive in the genus. Tufted plants produce hairy, carrot-like leaves. In late spring-early summer, arise stems 20-35 cm topped with a single relatively large yellow cup-shaped flower. After flowers fade, the stems continue to elongate 45-60 cm and develop impressive heads of silky-plumed seeds reminiscent of dandelions.

Ramonda myconi

Believed by many to be challenging, this hardy African violet relative is proving to be much easier in our region than anticipated. Plants form low evergreen rosettes. In late spring-early summer, many stems arise 5-10 cm with mauve African violet-like blossoms. Provide shade from afternoon sun and ensure excellent winter drainage and you will be surprised to find that this plant is not at all difficult to culture.

Ranunculus gramineus

The grass-leaved buttercup is perhaps the easiest of the alpine buttercups for us to grow in our region. Grass-like foliage forms a tuft to 15 cm. In early summer arise stems 20-30 cm topped with a loose cluster of waxy, yellow, saucer-shaped flowers. Plants may go summer dormant during hot spells but send up overwintering leaves in the fall.

Rhododendron impeditum

There are several dwarf rhododendrons that do well in our region. This one is perhaps the most attractive mainly due to its small, blue-tinted foliage that looks attractive year-round. In mid-spring, this low 10-20 cm. shrub is covered in stemless clusters of purple-blue flowers. ‘Ramapo’ and ‘Purple Gem’ are two additional dwarf rock garden rhododendrons which are widely available in our region.

Rhodiola rosea

Roseroot is native to coastal regions throughout our area. It makes an admirable rock garden subject. Plants form a mound of blue-green to gray-green, leathery foliage 10-30 cm. In early summer, their upright stems terminate in a flattened cluster of yellow, star-like flowers. Plants are monoecious with separate males and females. The males generally have the showiest flowers. Unlike their close relative, Sedum, this plant is completely herbaceous.

Scabiosa lucida

This dwarf pincushion-flower forms an evergreen mound 10-15 cm. high. Throughout the summer, stems arise 15-20 cm topped with several 5 cm diameter lavender-blue flowers.

Sedum cauticola ‘Lidakense’

This choice stonecrop is attractive from spring to fall due to its succulent, purple-gray foliage. In late summer-early fall, the 20 cm somewhat trailing stems terminate in a flattened cluster of purple-pink, star-like flowers. It is one of the best alpines for extending blooms into the fall season.

Veronica prostrata

This trailing speedwell forms an evergreen mat 5-10 cm in height. In early summer, plants produce spikes of bright blue flowers that continue over several weeks.

---