Groundcovers

The groundcovers in this half of the demonstration area use half as much water as bluegrass or less

  1. Erigeron glaucus ‘Olga’ is a dense, dark green rosette, 3” – 4” high and 5”-10” diameter. The flowers, on stalks to 6”-12” tall are 11/2” daisies with pale lavender rays and yellow centers, blooming June to November. Filled in quickly and looked good all year.
  2.  Delosperma Lesotho Pink: Very cold hardy iceplant with low evergreen foliage 1″ x 16″. Bright magenta pink flowers cover the plant in mid-late spring. Fairly drought tolerant. Quite heat tolerant. It has performed strongly for 5 years
  3. Delosperma ‘Kelaides’ was planted in the spring of 2002. It is reported to be a dwarf sport of the hardy iceplant D. cooperi with iridescent, salmon-pink flowers, vigorous, compact and floriferous, to 2” tall. It held up well in the heat of 2002; its drought tolerance is yet unknown.
  4. Sempervivum arachnoides and other ‘Cobweb Hen & Chicks’ look good in all seasons, but are filling in very slowly.  They make tight clusters of rosettes covered with white “webbing”, ½ – 3” tall, evergreen, eventually filling in densely, crowding out weeds.  The rosy red-pink star-like flowers are held on leafed stalks several inches above the rosettes, and the rosette that blooms will die after flowering.
  5. Thymus Back Wall: Very low creeping thyme ½” x 8″, looks similar to Elfin Thyme (Thymus minus) but holds up better. It is still vulnerable to drying in the winter because it is evergreen and shallow rooted like other thymes. Great between flagstones and around rocks, especially with winter and afternoon shade.
  6. Aethionema grandiflora, a species of Lebanon Stonecress, is an 8”–10” tall sub-shrub, spreading to 10”-12” wide, with very blue foliage. In May, the ends of the branches burst into bloom with small, fragrant pink flowers that smother the plant, continuing into June.  Loves sun and seems to thrive on drought.  Aethionema grandiflora is very beautiful, evergreen, and has proved successful in many Boulder-area gardens. It is not a true groundcover.
  7. Dianthus Blue Hills: perhaps the bluest foliage of all dianthus, 4″ x 12″. Very fragrant, vivid deep pink flowers in spring/summer. Somewhat drought tolerant, very dense for weed suppression. A beautiful plant.
  8. Penstemon virens: low, evergreen native penstemon 4″ x 10″, really a mat more than a groundcover. Intense sky-blue flowers in spring. Tough and sweet. Great between rocks, as a specimen and for small masses.
  9. Iberis (Evergreen Candytuft) dwarf varieties: here we are testing Iberis sayana – 4” x 12”, Iberis saxatilis – 3”-6” high mounds spreading to 12”-18”, and Iberis taurica.  All are evergreen perennials for sun or part-shade, with narrow, rich, dark green foliage, covered with white flowers in spring.  They make dense mounds and are mostly very drought-tolerant.
  10. Erodium chrysanthum: dense 8″tall perennial spreads 12″-24″. Fern-like foliage is almost evergreen and very attractive. Pale yellow geranium-like flowers bloom profusely for a month and then lightly for 2 more months. A big taproot makes this quite drought tolerant. Very tough and attractive. Can be massed for ground cover.
  11. Aubrieta deltoidea ‘Purple Gem’ (Purple Rock Cress) is a dense gray-green mat 4”-6” high and 8”-12” wide, blooming with small four-petaled purple flowers in early spring. It is evergreen and quite drought tolerant. Shear off flowers after blooming. It is a dependable performer, tolerant of many soils and conditions. It was fast to fill in.
  12. Globularia cordifolia has tiny dark green leaves which form dense woody, evergreen mats 1”-3” tall. These grow slowly and are not generally used as a ground cover, however for small areas and around flagstones and around stones in general, this Globe Daisy can be superb. It flowers with ½” round blue, ball-like flowers on short stems. While not tolerant of extreme drought, it likes sun and alkaline soil and will do well with little watering if given protection from winter sun.
  13. Eriogonum umbellatum ‘Kannah Creek’ is a fine variation on the mountain native Sulphur Flower. This xeric perennial has evergreen mounds of leathery oval leaves 4”-8” high and 16”-20” wide, with sulphur yellow flowers in umbels on 10” stalks. ‘Kannah Creek’, however, has mahogany fall, winter and early spring color and the yellow flowers start out brownish, giving a two-tone effect. It was fast to fill in and has a long blooming period, with the dried flowers continuing to be attractive. Hard to find, but worth it.
  14. Paronychia kepela: a very low, tight, evergreen groundcover, ½” x 16″ that looks similar to thyme but is more drought tolerant. Flowers are not showy but a white bract is colorful. Good for a low groundcover and between flagstones where thymes burn up in too much sun and drought. We call it Tough As Nails aka Nailwort
  15. Teucrium ‘Harlequin’s Silver’: found at Harlequin’s in a group of seedlings of T. cossonii. It makes a dense mat 4″-8″ high by 16″-24″ wide with very silver aromatic foliage that is unattractive to rabbits and grasshoppers. It blooms in summer with pink-lavender flowers. The foliage is gorgeous in winter.
  16. Satureja montana illyrica is a compact winter savory with leathery leaves and woody stems. The flowers are blue to violet over a long period in the fall. It grows 6”-8” high and 10” in diameter. The foliage is very attractive and the plant is tough, needing little water.
  17. Phlox subulata ‘Boothman’s Variety’ is a fast spreading Moss Phlox 3”x18”-24” wide. The flowers are a vivid lavender blue with a dark purple eye. This variety has held up better in heat and sun than others, though it also does well in part shade. The leaves are needle-like and evergreen. Moss Phlox does well covering large areas. The foliage looked dry this spring, but it recovered quickly and bloomed well, and again in fall.
  18. Herniaria glabra (Rupturewort) has rich, dark green foliage 1” tall. Filled in a 2’ x 3’ space very quickly.  It is evergreen, with insignificant, tiny flowers.  Makes an excellent groundcover for dwarf bulbs and could be used between stepping-stones, or to edge a walk. It looks good 12 months of the year.
  19. Waldsteinia ternata (Barren Strawberry) has attractive strawberry- like leaves and the 6”x12” plants grow together to form a mat. The flowers bloom in early spring a deep yellow. It tolerates dry shade very well, but was somewhat burned this spring. It recovered quickly once irrigation was turned on.
  20. Lamiastrum gal. ‘Herman’s Pride’ (Yellow Archangel) has 8”-12” vertical square stems with nettle-like leaves, pointed and coarsely toothed, with beautiful silver markings. In June/July it flowers with yellow, lipped flowers. It can tolerate sun or shade. Perhaps it is best used in dry shade. It filled in the test bed quickly and looks good most of the year.
  21. Alyssum oxycarpum: a dwarf, low Basket of Gold 4″high and 18″ wide with gorgeous silver foliage summer and winter. Rich yellow flowers in spring. Wonderful rock garden plant or low mat for the front of the border.
  22. Geranium cant. ‘Biokovo’ has evergreen, lobed leaves that are fragrant when rubbed, which turn red in the fall. The plants grow densely inhibiting weeds and spread rapidly 8” high and 16”+ wide. The flowers are a pale pink and bloom for a long time. The species Geranium cantabrigiense is very similar with darker pink flowers. Both are tolerant of different soils, sun or shade and do well dry.
  23. Geranium dalmaticum is an evergreen hardy geranium that makes a dense mound 6”x12” of fragrant foliage that turns red or orange in the fall. The flowers are 1” wide of a clear pink and are long blooming. It grows in sun or shade, but looks better in part shade if very dry.
  24. Delosperma Fire Spinner: Introduced by Plant Select in 2012 Low, evergreen iceplant, 1″ x16″. Very showy flowers have hot pink/lavender centers with orange ray flowers. The shiny green, succulent foliage spreads quickly
  25. Delosperma ‘John Proffitt’ (Table Mountain Ice Plant) has wedge-shaped foliage which is very dense, fast-spreading, and is turgid and is tinged purple in winter. It grows 2”-3” high and 16”-24” wide. The very long blooming flowers are a purple red with a creamy eye. It is reported to be more cold hardy than D. cooperi. It has performed very well so far.
  26. Scabiosa lucida is a dwarf pincushion flower 4”-8” high and 12” in diameter. It is not really a ground cover but mounds densely to cover the ground and suppress weeds. The small rosy-lilac flowers are on short stems and bloom for a long, long time even under low water conditions as it has a big tap root. It can self sow in moist soil.
  27. To be replanted.
  28. To be replanted
  29. Prunella grandiflora (Self Heal) is usually grown as a part-shade plant, and has done better than expected in full sun with little water. It filled in quickly and densely 5”-6” high and 18” wide, shooting up to 12” when it flowers. The showy dark violet-purple flowers are lipped and hooded and bloom in clusters in June and July, sometimes longer. It is excellent in dry shade, good for suppressing weeds, and is possibly too aggressive under moist conditions.
  30. To be replanted
  31. Cerastium candidissimum is a low-growing Snow in Summer that has dense, very silvery foliage 1”-2” high and 8”-12” wide. It has beautiful white flowers in spring. It is slow to establish and needs some water for the first year. In the second year it is looking beautiful even in winter. It doesn’t flop like C. tomentosa, but it is best to dead-head.
  32. To be replanted
  33. Veronica cuneifolium is a very dense creeping veronica that filled in quickly. The foliage is beautiful, gray-green, toothed and evergreen to 3” high by 12” wide. The flowers are a good blue with white markings, blooming in spring. It is perhaps not the most drought tolerant creeping veronica, but it held up well in 2002.
  34. Alyssum pateri: a little-known dwarf Basket of Gold. Yellow flowers on a 4″ mat. It took a couple years to fill in, but now it seems strong and durable.
  35. Potentilla neumanniana ‘Nana’ is a dwarf cinquefoil without runners, making a mound 3”-4” high and 12” in diameter. The flowers are a golden yellow and bloom spring into summer. It looked stressed this spring, but perked up with a little irrigation. For eight years a specimen starred in my xeriscape garden.
  36. Dianthus gratianopolitanus is a rugged Cheddar Pink from Europe. It filled in rapidly, making a dense, evergreen mound 6”-8” high and 12” in diameter, extending to 12” in flower. It blooms in June/July with single pink, very fragrant flowers. Our strong winter sun may burn it, but it still may prove successful. Shear after flowering.

The groundcovers in this half of the demonstration bed use only one fourth as much water as bluegrass

  1. Achillea serbica is mat-forming Serbian Yarrow. It has beautiful, silvery gray, evergreen foliage 6” high and 12”-16” in diameter that filled in quickly. In May/June it blooms with pure white daisy like flowers with a yellowish eye. It is quite xeric, but can burn our in extreme conditions. It is best to shear after flowering. It is almost identical to Achillea ageratifolia.
  2. Penstemon pinifolius ‘the orange-flowered form of the Pineleaf Penstemon. It is 4” tall in spring and 10”-15” high in bloom. It is beautifully evergreen through winter making 12” diameter mounds. The leaves are pineneedle-like, and the flowers are narrow and tubular and bloom profusely over a long period.It filled in quickly.
  3. Achillea kellereri: narrow bluish fern-like foliage 6″-8″ high, 8″-10″ wide, white flowers with silver centers are 12″-14″ high. This is not a suckering yarrow. Beautiful and well-behaved. Low water. Supports bees and butterflies and is not attractive to deer and rabbits. Plant 10″ apart to make a groundcover.
  4. Dog Tuff Grass: very low lawn grass, tested and promoted by Kelly Grummons. Drought tolerant, dog play and pee tolerant, beautiful color, the pollen is loved by bees. Spreads by runners, does not tolerate shade, green June through September. Easy to manage organically; from Africa-similar to buffalograss, but more tolerant of foot traffic
  5. Teucrium chamaedrys compactum is a dwarf germander growing 5”-8” high and 8”-10”wide. The foliage is glossy, scalloped, dense and weed-smothering. The flowers are rosy purple, blooming in summer. It tolerates dry and infertile conditions. We are still testing this compact variety; the non-compact form is industrial tough.
  6. Marrubium rotundifolium has beautiful felty, round, gray-green leaves with a cream edge. It grows to 4”-6” high and 15”-20” in diameter, and looks mostly evergreen in winter. The flowers are not showy and some people prefer to shear them to keep the foliage cleaner. It does well in dry, well-drained conditions. It was planted in the spring of 2002.
  7. Ephedra minima: low ephedra 3″-4″, plant 6″ apart for groundcover. Very xeric, very heat tolerant. Grassy, leafless stems with bluish color, red berries
  8. Veronica pectinata is a very fast growing creeping veronica that is evergreen, 3”-4” high and up to 4’ in diameter after several years. The violet-blue flowers with a white eye bloom very early in the spring and again a little in the fall. Spots can rot with too much water or burn out with too little, and still it is a valuable groundcover. Shear flowers after blooming and rub out brown areas with a gloved hand to regrow and fill in.
  9. Sedum to be identified
  10. Teucrium rotundifolium: a little-known Germander from Spain. 4″ x 24″. Very xeric and strong grower with violet-purple flowers. It has done well in the ground, grown dry for 12 years.
  11. Anthemis marschalliana: a Plant Select introduction. Fine textured mat of silver foliage 4″-8″ high and 12″-16″ wide. Blooms late spring with bright yellow daisies on 10″ stems. Very beautiful perennial. Plant 10″ apart for groundcover
  12. Anacyclus depressus (Atlas Daisy) is an evergreen mat of grayish lacy foliage 3” high. The flowering runners are prostrate, up to 12” long, and produce attractive 1” white daisy flowers with yellow centers. The undersides of the petals are red which shows when the flowers close on cloudy days. It is extremely drought tolerant and filled in quickly. It may be necessary to cut off the “runners” after flowering. It can be somewhat short lived, but self sows. It is tap-rooted and industrial tough.
  13. Veronica allioni: a creeping veronica with blue flowers in spring on 6″ spikes. Good small groundcover and wonderful in a rock garden, among stones or the front of the border. This is the true V. allioni
  14. Ohme Garden Thyme: a very vigorous and tough creeping thyme, 3″ x 24″; evergreen foliage , flowers in the summer with purple-pink flowers
  15. Reiter Thyme: wide-spreading and tough evergreen creeping thyme, 3″ x 30″; mauve-pink flowers in summer, very tolerant of foot traffic
  16. Veronica liwanensis (Turkish Veronica) is 1”-2” high evergreen mat to 24” in diameter with small glossy, dark green leaves. In spring it blooms, covering the foliage with cobalt blue flowers. It is good to shear all the veronicas after blooming. It tolerates some shade and is very xeric. It was a Plant Select winner in 1997.
  17. Veronica oltensis, Thyme-leaf Veronica is very low ½”-1” and 24” wide. It is evergreen and xeric, with tiny oak shaped leaves. The spring flowers are an azure, sky blue, tucked into the foliage. It can be used between flagstones or it will spread widely as a real groundcover.
  18. Veronica Crystal River: a hybrid creeping veronica with beautiful blue flowers on 2″ x 20″ evergreen mat. Very vigorous and fast-growing. A very good western groundcover and good in rocks.
  19. Veronica tauricola is another creeping veronica with beautiful silvery gray leaves, making a mat 2” high and 12”+ in diameter. It quickly filled in the bed. In spring the blue flowers are outstanding against the silvery foliage. It is new to commerce and we need to test it further, but it looks very promising.
  20. To be replanted
  21. Thymus serphyllum ‘coccineum’ (Red Creeping Thyme) is 1”-2” tall and 18” wide, and blooms rose-red in June/July. It filled in quickly and is evergreen and drought tolerant. It has performed very well and seems very durable. Very showy in flower.
  22. to be replanted
  23. Clear Gold Thyme mounds 2”-4” high and 12”-16” in diameter with good gold-tinged foliage. It is evergreen and looked very attractive last year. In the spring, however, it looked burned, but now has recovered very well. We will test it further.
  24. to be replanted.
  25. to be replanted.
  26. Woolly Thyme is a low groundcover ½”-3” high and spreads up to 18”-24” in diameter. It is evergreen and works well between flagstones or planted in a large area. It can die out in patches, but generally is very successful. It filled in quickly and rarely flowers.
  27. Thymus minus is a very tight, low thyme ½”-3” high and 18” wide. It is very slow-growing but excellent between flagstones. In summer small pink flowers bloom close to the evergreen foliage. It does burn in winter sun, so some protection or supplemental water may be helpful.
  28. Sedum spurium ‘Bronze Carpet’ is an evergreen goundcover growing 2”-3” high and 24”+ wide. The stems creep along the ground, rooting as they go. The foliage is a good bronze color most of the season. The flowers bloom in summer with a purplish-pink color. It spreads quickly and is very durable.
  29. Sedum hybridum Kazakstan: a very strong, evergreen sedum with yellow flowers, recently planted
  30. Sedum hybridum is an evergreen succulent 3” high and creeps 12”-18” or wider. The flowers bloom yellow in summer and sometimes again in fall. In late fall, the foliage can turn a dark red. It was planted in the spring of 2002.
  31. Sedum album (White Moss Sedum) is an extremely drought tolerant and wide spreading succulent. Any pieces that break off its rich evergreen foliage will root. However it is not hard to dig out if undesired. The white flowers are refreshing as they bloom in the heat of summer. Dead-heading must be done by shearing, not pulling.

COPYRIGHT 2018 HARLEQUIN’S GARDENS

Copying this material is not permitted without permission 303-939-9403