Culture
Grow in organically rich, fertile, medium moisture, well-drained soils in full sun. Best with cool, moist winters and warm dry summers. Plant bulbs 4-6” deep (three times the depth of the bulb) in fall. In heavy clay soils, a slightly shallower depth is best. Space bulbs 2-5” apart depending on plant size. Tulips may be grown as perennials or as annuals. Species tulips often perform better than hybrid plants as perennials. When growing tulips as perennials, promptly remove spent flower stems after bloom (prevents seeding), but do not remove foliage until it yellows. In most cases, tulip performance declines substantially starting with the second year. Many growers prefer growing tulips, particularly hybrids, as annuals.
'Stressa' is one of the Kaufmanniana tulips that are noted for being long-lived perennials, however they may be grown as annuals. When grow as perennials, spent flower stems should be promptly removed after bloom, but foliage should not be removed until it yellows. Best performance occurs in USDA Zones 3-7.
Noteworthy Characteristics
Tulipa is a genus of about 100 species of perennial bulbs found from sea level to alpine areas in Europe, The Middle East and Asia where they are the most diverse in Central Asia. They are popular spring flowers that come in nearly all colors except true blue. Shape is often a cup with a teardrop form. Bowl, goblet and star shapes also exist. Some flowers are double. Each flower has six petal-like tepals. Tulips are generally organized into 15 divisions based upon flower shape and origin. Bloom time varies.
Genus name comes the Latinized version of the Turkish name tulbend meaning a turban.
'Stressa' is one of the Kaufmanniana tulips, which are commonly called waterlily tulips because the petal-like tepals open out horizontally in full sun, giving the flowers a waterlily-like appearance. Flowers bloom singly or in small clusters. Flowers typically close up at night. 'Stressa' blooms very early (March). Each flower is bright yellow with red stripes, and has a yellow interior. Flowers grow to a compact 8-10" tall. Broad, tapered leaves are green but attractively mottled with darker green to brown stripes.
Problems
Bulb and root rots may occur, particularly in wet, poorly drained soils. Gray mold. Mosaic virus may also occur. Animal pests include aphids, slugs and snails. Mice and voles are attracted to the bulbs. Squirrels may dig up newly planted bulbs.
Uses
Plant in large groups or mass for a stunning spring display. Use smaller groupings or scatter in a mixed borders, cottage gardens, or cutting gardens. Long-stemmed varieties are particularly well-suited to use in fresh cut arrangements. Can be used in spring container plantings.
Beds, borders and rock gardens. Containers.