DESCRIPTION: Saxifraga is a large group of hardy perennial plants. Only a few are annuals or biennials. They are mostly natives of North and South Temperate and Arctic regions. A few are found in Asia and they are rare in South America. The name is an old Latin name derived from saxum, a rock and frangor, to break; the plant was thought to break stones in the bladder. Rockfoil is a common name given to Saxifrages. The Saxifrages are a varied group of plants and botanists have divided them into a number of sections. The Kabschia, the Engleria and the Porphyrion sections are the earliest kinds; they bloom in January and February. The others are Dactyloides, Euaizoonia, Diptera, Trachyphyllum, Hirculus and Cymbalaria. These plants are mostly used in the rock garden but one, S. sarmentosa, is often grown in greenhouses and homes. They have pretty flowers and handsome foliage and a long flowering period. The Silver Saxifrages (section Euaizoonia) grow best among rocks or in the dry wall. They have silver rosettes of foliage and sprays of white, yellow, or pink flowers. Kabschia Saxifrages should be grown in an open area, which preferably slopes toward the west or northwest rather than south. A few of these kinds do best if they're planted in a deep, narrow crevice in a rock. This group is also great for growing in pots and pans in an alpine house. They flower in early spring and their beautiful, dainty flowers form perfectly under glass.
POTTING: The Dactyloides or Mossy Saxifrages - These plants need a cool, partially shaded spot with a lot of room to spread. They grow very quickly. After these plants flower, it would be smart to top-dress the clumps with a fine mixture of sifted loam, leaf mold, and sand. You can pour this over the plants dry and carefully work it down between the rosettes with the fingers. If the soil mixture is fine and dry it should work down quite well. Water them overhead with a fine spray. With age, this group tends to become brown and patchy but this top-dressing keeps them healthy for a long time. Mossy Saxifrages with red flowers develop their vivid color in shady or partially shady spots; full sun just fades the color.
The Kabschia Saxifrages -They should be potted in soil consisting of loam, sand and leaf mold, with a generous amount of crushed stone added. Excellent drainage is a must and many buried stones help. As the plants grow, they should be top-dressed with fine soil that is worked down into the rosettes and stems. Fine loam, sifted leaf mold, sand and crushed rock may be used in a dry state after flowering and in the early fall. When they are used for houseplants, they should have the same soil mixture as described above. The crushed stone should be limestone. Another thing that should be added is crushed or broken flowerpot. Start with extremely clean pots and make sure they have adequate drainage. Never allow them to become very dry, but do not over water them. If you are over watering, the leaves will turn yellow. They need good ventilation and shade during the summer. Saxifrages grown in the home should also have a top-dressing as described above. They can be repotted when they've filled up their pans or pots.
The Euaizoonia or Silver Saxifrages: They grow best in well-drained loam among rocks or in the drywall.
PROPAGATION: Seeds, cuttings and division can be used to increase your stock. Mossy Saxifrages, such as S. umbrosa primuloides, strong Kabschias, such as S. apiculata and many of the Silver Saxifrages can easily be increased by lifting the plants and pulling them into pieces that have some roots attached and replanting them. In spring, early summer or fall, single leaf rosettes are removed with as much base stem as possible. Remove a few of the lower leaves and insert them into a pan of sand in a closed cold frame. They root easily and in a few weeks may be transplanted into small pots until they're large enough to plant in the rock garden. S. longifolia must be increased by seeds, which can be sown in a pan of loam, leaf mold and sand in a cold frame. When they are large enough to handle, plant them in small pots until large enough to plant in the rock garden. The Engleria Saxifrages are increased by leaf rosettes that are removed with as much of the basal stem as possible and treated like the cuttings described above. S. oppositifolia can be propagated by cuttings, too. Short side shoots are removed after flowering and rooted in pans of sand in a closed and shaded cold frame. Large plants can be divided and replanted.
VARIETIES - The following are natural species of Saxifragas, Some of which have been described for you: F = flowers L = leaves.
S. aizoides - Common in boggy places & streamsides. L. forms mats, dark green, mossy, 3-4" high, F. golden-yellow. Varieties are aurantia (F. orange) & atrorubens (F. dark mahogany red);
S. ajugifolia - It's a rare dwarf mossy kind only growing 2-3" high. F. in heads, white;
S. apiculata - It's a hybrid & one of the prettiest of the Kabschias group. Rapid grower, L. shiny, emerald cushions growing in sm. rosettes, F. early spring, profusion of flower heads about 2" high, primrose-yellow blossoms; S. apiculata alba - white variety;
S. arachnoidea - The Cobweb Saxifrage is extremely rare, found in only a few spots of Trentino. Lives in the mouths of caves & hollows high up in the mountains. It's an annual or biennial. L. & stems are covered w/ long, glistening, glandular hairs, F. pale gold;
S. Brunoniana - L. sm. rosettes, pale green w/ bristly hairs, multiplies by sending out strawberry-like runners on pink, thread-like stems, F. lg., yellow, grow on leafy stems;
S. canaliculata - L. dark green, sticky & fragrant, F. lg. & white.
S. Clarkei - It's a hybrid. L. pretty silver rosettes, F. in heads, pink, 3" stems, early spring;
S. Cotyledon - L. lg., shiny, green rosettes, slight silver at edges, many side rosettes, F. 2 ft., arching sprays, white. Each rosette dies after flowering, but new ones have grown to replace it. Varieties are pyramidalis, icelandica, caterhamensis;
S. Dr. Ramsey - L. in shapely rosettes, blue-green, heavy silver changing to purple & red in winter, F. abundant, round, white w/ red spots, spike is about 9" high & arched slightly;
S. Elizabethiae - L. grow in cushions, rich green, F. many heads, primrose yellow, reddish stems, 2" high;
S. geranioides - Large foliage, F. pure white, 6-8" stems, a fragrant plant. Its variety ladanifera has leaves coated w/ a resinous substance that gives a blue-gray color and intensifies the aroma of the plant;
S. granulata - The Meadow Saxifrage grows in damp meadows in Europe. L. scalloped, broad, F. on a branched head, pure white, stem - 9-12" high. Variety, flore-pleno, has double flowers.
S. Grisebachii - L. in beautiful rosettes, heavily silvered, F. unnoticeable, hidden by the red, velvety fur that covers the upper portion of the spike, which has blue-green leaves edged w/ silver. A variety, Wisley, has larger rosettes & flower spikes covered w/ more red velvet;
S. Hostii - F. cream white speckled w/ red on tall spikes;
S. Iris Prichard - L. gray-green cushions, F. lg., rose-apricot, on inch long stems;
S. lilacina - A dwarf. L. in close mats, gray-green, F. lg., lilac, on stems ½" high;
S. lingulata - Grows on limestone formations in Italy, Spain & Sicily. L. in rosettes, long, narrow, blue-gray edged w/ silver, F. white, carried on long, plumy sprays that arch out elegantly. Varieties are Australis (F. pure white or spotted w/ red), Bellardii, Catalaunica, Lantoscana & superba;
S. media - L. in rosettes, blue-green, F. sm., pink, on 2-3" spikes that are covered w/ red velvet;
S. Myra - a dwarf hybrid, L. gray-green, F. cherry red on inch high stems;
S.sarmentosa - The Strawberry Geranium or Strawberry Begonia is a trailing plant. L. coarsely toothed, fuzzy, reddish beneath & veined w/ white above, F. white, 2-5 petals are longer than the others, grow on a branched stem, 18" to 2' high. A variety is S. sarmentosa tricolor, which has cream white & rose-red variegations;
S. umbrosa - In Great Britain is known as London Pride, St.-Patrick's-Cabbage, Prattling Parnell & Prince's-Feather. L. stiff rosettes, green, F. rose-pink & are spotted. Varieties are Melvillei, Ogilvieana, variegata, primuloides & Elliott's Variety;
Below are more natural kinds that have varieties:
S. Aizoon & varieties Balcana, Elongata, Flavescens, Hirsuta, Intacta, Labradorica, Lagraveaba, Lutea, Major, Notata, Pectinata, Punctata, Punctatissima, Rex, Rosea and Rosularis;
S. Burseriana & varieties Gloria, Grandiflora, magna, speciosa, crenata (its petals have crimped edges), S. Burseriana sulphurea;
S. decipiens & varieties bathoniensis (F. red), Rhei (F. pink), Guildford Seedling (F. bright red), Fergusonii (F. bright pink), Diana (F. lg., white), Fairy, Glasnevin Beauty, sanguinea superba;
S. Fortunei & variety S. cortusaefolia;
S. Geum & varieties crenata (L. edges are scalloped) & hirsuta (L. very fuzzy);
S. hirculus (a bog plant) & variety major or grandiflora;
S. longifolia & varieties Cecil Davies, Tumbling Waters;
S. marginata & variety Rocheliana;
S. moschata & varieties atropurpurea, compacta, glandulosa, laxa, Allionii;
S. oppositifolia & varieties Alba (F. white), Latina (F. pink), Splendens (F. heather purple) & Wetterhorn;
These are more natural varieties:
S. ada; S. androsacea; S. aquatica; S. aretioides; S. aspera; S. bertolonii; S. biflora; S. borisii; S. boryi; S. caesia; S. caespitosa; S. camposii; S. cartilaginea; S. cernua; S. chrysantha; S. cochlearis; S. cortusaefolia; S. cortusaefolia fortunei; S. corymbosa; S. crustata; S. cuneifolia; S. diapensioides; S. Ferdinandi-Coburgii; S. hypnoides; S. Irvingii; S. juniperifolia; S. Kellereri; S. kestoniensis; S. kewensis; S. Kotchyi; S. mutata; S. pedatifida; S. porophylla; S. retusa; S. sancta; S. scardica; S. Sibthorpii; S. squarrosa; S. Stribrnyi; S. Sundermannii; S. tenella; S. tennesseensis; S. tombeanensis; S. Tumbling Waters; S. turfosa; S. valdensis.
The following are hybrid Saxifragas:
S. Andrewsii; S. arco-valley; S. biasoletti; S. Bileckii; S. Boydii; S. Boydii alba; S. Burnatii; S. bursiculata; S. Cherry Tree; S. Churchillii; S. Cranbourne; S. Delight; S. Esther; S. Faldonside; S. Forsteri (a natural hybrid); S. Gem; S. Godseffiana; S. Haagii; S. His Majesty; S. Jenkinsae; S. Macnabiana; S. Mrs. G. Prichard; S. Obristii; S. patens (a natural hybrid); S. Paulinae; S. pectinata; S. Petraschii; S. primulaize; S. Riverslea; S. Salomonii; S. tyrolensis (a natural hybrid).