Origanum General Information Germ Time : 20 -30 days growing light needed Origanum are perfect for rock gardens. Ornamental Oregano is an attractive flowering perennial that is easy to grow. Must have good drainage, Avoid too moist (wet feet), Not for zones 3&4; may need to mulch or protect in Zone 5. Origanum Plant Care This low-maintenance plant prefers average, dryish soil with good winter drainage. Can be divided every 3 - 4 years in the spring. Trim off old stems in spring when new growth appears. Benefits from gravel mulch. Snip off old blooms to extend flowering period. Not good for cooking but flowers are attractive when dried.