Common name: Saxifrage
Family: Saxifragaceae, Saxifrage
Height x width: 3-12" x 3-12"
Growth rate: moderate
Foliage: dense tufts of palmately dissected (x arendsii) or basal rosettes of oblong (paniculata); quite variable although sometimes reniform (kidney-shaped)
Flowers: rose to blood red (x arendsii) or creamy white (paniculata); spring, early summer
Hardiness: varies 2-7 to 7 with species
Soil: well-drained but moist, prefer neutral to slightly alkaline generally
Light: sun in north to part shade where warmer or shade for some species
Pests and Problems: rusts, aphids
Landscape habit, uses:rock gardens, wall gardens, trough gardens
Other interest: name comes from the Latin saxum meaning rock and frango meaning to break, refering to its nature of growing in rock crevices; another interpretation relates to its mention in the 16th century Doctrine of the Signatures as as cure for bladder or kidney stones ("to break stones") due to its kidney-shaped leaves.
Other culture: does not do well in heat and humidity; often very demanding of soil type and moisture, many only for collectors with specific controlled conditions
Propagation: seeds (several years to bloom), spring or summer division, cutting of single rosette
Species:
The 370 annual and perennial species have been divided in sections (and of interest primarily botanically, into subsections). Most references have a slightly different classification system. The one below is based on Gornall (Bot. J. Linn. Soc. 95(4):273-292, 1987) as described in Jelitto and Schatt, 1990 and includes 14 of the 15 sections which contain perennials or biennials.
Section--Latin characteristics
1.Euaizoonia Silver Rosetted, Encrusted; above-ground rhizomes, tough chalky rosettes
2.Porophyllum Early Spring Rockfoil; dense and firm rosettes, evergreen, chalky margins
3.Dactyloides Mossy Saxifrages; soft-leaved rosette, above-ground stolons, dense mat
4.Porphyrion small, leathery evergreen leaves, often prostrate stems
5.Robertsoniana evergreen, above-ground stolons, leathery basal rosettes
6. Diptera hairy with runners, rounded leaves, summer or fall bloom, likes humus soil
7. Nephrophyllum usually biennial, reniform leaves toothed or divided
8. Trachyphyllum evergreen, grass-like cushions, leaves simple
9. Xanthizoon evergreen, mats or cushions, alternate fleshy leaves lime encrusted
10. Cymbalaria biennial or annual, leaves alternate often fleshy and palmately lobed
11. Miscopetalum small and bushy, short above-ground rootstock, reniform toothed leaves
12. Boraphila tall 1-3' tall, thick rootstock, basal leaves, moist woodland acidic site
13. Tridactylites lime-loving, usually biennial, basal palmately lobed leaves, floriferous
14. Hirculus deciduous, clump-forming, basal leaves with petioles, late
summer, humus soil
The following are the more commonly available in commerce in the U.S.
Dactyloides section (3) consists of the Arendsii hybrids . Other hybrids
among several species are listed in the section most relevant. Zones
are for cold hardiness.
| Taxa (section) | zone | flowers | other | |
| aizoides (9) | 2-5 | yellow, orange cymes | low evergreen mat for moist, difficult | |
| aizoon:paniculata | ||||
| x andrewsii (1) | 3-6 | white | 8" high, loose rosettes | |
| x angelica (2) | 6 | red, often bright | blue to gray-green cushion of rosettes | |
| x apiculata (2) | 6 | white or pale yellow | floriferous | |
| 'Aureopunctata' (5) | 5 | white, pink | x urbium, golden variegated leaves, sun | |
| x biasolettii (2) | 6 | carmine red, especially buds | rosette leaves long, acute | |
| 'Blood Carpet' | 3 | carmine red | 4-8" tall, from seed | |
| 'Blutenteppich':'Blood Carpet' | ||||
| x boydii (2) | 6 | light yellow, few in groups | sea-green dense mats, small-leaved | |
| x burnatii (1) | 5 | white | natural hybrid of maritime Alps | |
| burseriana (2) | 5-6 | pure white, solitary | gray-green, prickly, early bloom | |
| callosa (1) | 7 | white spotted panicle, June | blue-gray channeled leaves | |
| cochlearis (1) | 6-7 | pure white, June | mounded clump of rosettes | |
| cotyledon (1) | 5-6 | fragrant white, arched | flat rosettes | |
| cymbalaria (10) | 6 | yellow, starry | low 2-4", for shade or dry crevice | |
| diversifolia (14) | 6 | rich yellow, few, racemes | clump-forming for moist shade | |
| var. egemmulosa (3) | 6 | white,few | green mats reddish in fall, hypnoides | |
| 'Flower Carpet' | 3 | reddish pink | 4-8" tall, from seed | |
| geranoides (3) | 6-7 | white bell-shaped cluster | 8" tall, leathery, hairy, fragrant leaves | |
| grisebachii (2) | 6 | bluish pink, spike-like | high-humped colony of rosettes | |
| hirsuta (5) | 6 | white, many in panicles | long-stalked hairy basal leaves | |
| hostii (1) | 6 | white spotted, flat corymb | quickly mat-forming | |
| hypnoides (3) | 6 | white, few | loose mat to dense grass-like | |
| x irvingii (2) | 6 | lilac-pink, darker eye | vigorous, spiny, gray-green, very early | |
| x kellereri (2) | 6 | pink, long branched stems | gray rosettes, very early | |
| kingii: hypnoides var. egemmulosa | ||||
| kotschyi (2) | 6 | yellow, small in corymbs | mounded, dense cushion | |
| 'London Pride':x urbium | ||||
| x megaseiflora (2) | 6 | bright rose, solitary in 2-3s | dwarf 1-2", gray hard cushions | |
| mutata (1) | 5-6 | yellow, orange panicle | short-lived, rosettes die after flw. | |
| oppositifolia (4) | 2-7 | red shades | flat cushion mats, variable site needs | |
| paniculata (1) | 2-5 | white umbellate panicles | quickly mat-forming of rosettes | |
| x paradoxa (1) | 5 | cream white | silvery cushion, natural hybrid | |
| pedemontana (3) | 6 | white, false umbel | pale green carpet, leafy | |
| pensylvanica (12) | 5 | greenish white, small | 2-3' tall, 1' leaves, for moist shade | |
| 'Purple Carpet' | 3 | deep purple | 3-4" tall, from seed | |
| 'Purpurteppich':'Purple Carpet' | ||||
| rosacea (3) | 6 | white or pale pink, 2-5/stem | variable habit with cultivar | |
| rotundifolia (11) | 6 | white, rose spots, floriferous | 1-2' tall, bushy for moist shade | |
| x salmonica (2) | 6 | white, red buds, floriferous | dense mats, short-lived | |
| 'Snow Carpet' | 3 | white, large | 5-7" tall, standard | |
| spruneri (2) | 8 | white, small, corymb | small cushiony cluster | |
| stellaris (12) | 2-6 | white, starry, yellow spots | requires gritty, moist, well-drained | |
| stolonifera (6) | 5-6 | white, red spots | popular houseplant, thread-like stolons | |
| 'Tricolor' (6) | 5-6 | white, red spots | stolonifera, leaves green, white, pink | |
| umbrosa (5) | 6-7 | white, red spots | usually mistaken for x urbium | |
| x urbium (5) | 7 | white, starry, small, red inner | dense, dark green carpet | |
| valdensis (1) | 6 | white, June, small | dwarf 1", hemisphere rosette | |
| 'Variegata':'Aureopunctata' | x urbium | |||
| veitchiana (6) | 7 | white to pink, few | dark green above, brown below, stolons | |
©Authored by Dr. Leonard Perry, Professor, University of Vermont as part of PSS123 course.
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