Alyssum, Perennial

ALYSSUM, Perennial Cruciferae A. species

HABITAT: Native Mediterranean area. Hardy zones 3-10 depending upon species.

USES:  Rock garden, wall, border, edging, or ground cover.

HABIT:  Low growing, mounded plants which are covered with masses of tiny, four-petal flowers, May-frost (depending upon varieties).  Height varies from 3-18 inches.  Perennial species lack the honey-like fragrance of the annual species except A. montanum.

SEED GERMINATION:  Sow seed early fall or early spring outdoors or sow indoors 8-10 weeks prior to last frost, in peat pots or pellets.  Cover seed to their thickness.  Germination usually takes 6-10 days at a soil temperature of 60 degrees Fahrenheit.  Shift to permanent garden location when roots emerge from pot walls.

CULTURE:  Set out in full sun in sandy, gravelly soil with extremely good drainage.  A soil pH of 6.8-7.0 is best.  Give light to moderate fertilization with a all purpose fertilizer; keep plants moderately moist. Some species are short lived unless sheared after blooming to promote new growth. Division every third spring restores old clumps and prevents excessive spreading of some species.

SPECIES:  A. montanum:  Zone 3.  Similar to the common A. saxatile but neater (8"); fragrant flowers blooming April to August.  Gray foliage.
A. murale (yellow tuft):  Zone 3.  Medium yellow flowers on 18 inch stems in January-July.
A. saxatile (Basket of gold, golden tuft):  A sprawling, more common species with clusters of tiny, yellow flowers on 12 inch stems.  A double form exists which is most desirable.  Flowers from May-June.  Zone 3.
A. serpyllifolium:  A dwarf, 2 inch rock garden plant with tiny foliage and bright yellow flowers.  Zone 4. June-August.
A. spinosum:  White flowers in May-July on a silvery, 12 inch mound.  A rose color is also available. Zone 6.

INSECTS:  Flea Beetles:  Use an approved insecticide such as Malathion or Captan for control.

DISEASES:  Damping Off:  Remove dead and diseased plants. Drench with Thiram or Captan for control.
Leaf Spot:  Use an approved fungicide such as Captan, Maneb, or Zineb for control.
Clubroot:   Improve drainage.  Lime soil 6 weeks prior to planting to raise soil pH to 7.2 or higher.

PROPAGATION:  Soft wood cuttings, division, seed.

REMARKS: Low growing, hardy plants exceptionally valuable for rock gardens and walls.  For a unique treatment, try them as a ground cover.