Annual
Signet Marigold
Tagetes tenuifolia · Asteraceae
Also called: Signet marigold, Golden marigold, Lemon marigold, Gem marigold, Tagetes signata (synonym)
Signet Marigold (Tagetes tenuifolia) is a low-water annual well suited to Tucson and the low desert. It's a fast-growing annual.
Signet Marigold at a glance
- Water use
- Low (established)
- Sun
- Full sun for densest mounds and best bloom; tolerates light afternoon shade in extreme heat.
- Mature size
- 8-12 in tall and wide, forming a compact, lacy, ferny-leaved mound
- Growth rate
- Fast
- Bloom
- Yellow, gold, and orange (small, single, daisy-like flowers, often with a delicate citrus fragrance), Spring through early summer and again in fall; covered in small single flowers when in season.
- Cold hardiness
- Frost-tender; killed by frost. Heat-tolerant but, like other marigolds, blooms best before peak midsummer heat and again in fall.
- Soil
- Well-drained soil amended with compost; tolerant of alkaline desert soils.
- Native range
- Mexico and Central/South America; grown as a cool-to-warm-season annual in Tucson
- Best used as
- Edible flowers (petals have a citrus/tarragon flavor for garnishes and salads), Edging and borders, Containers and window boxes, Pollinator and companion planting, Herb gardens
- Wildlife
- Attracts bees and butterflies; aromatic foliage helps deter some pests and rabbits.
- Toxicity
- Non-toxic; flowers are edible (the 'Gem' series - Lemon Gem, Tangerine Gem - is grown for culinary use). Safe around pets and children.
How to grow Signet Marigold in Tucson & the low desert
Watering
Plant in spring (March-April) and/or late summer-fall (September) for fall color. Water deeply 2-3 times per week; water at the base and keep foliage dry to avoid fungal issues. More heat-forgiving and finer-textured than tall African marigolds.
Fertilizer & nutrients
Light feeder. Compost plus a balanced fertilizer at planting and an occasional light feeding is plenty; avoid excess nitrogen to keep blooms coming.
Pruning & care
Largely self-cleaning; shear lightly mid-season to refresh the mound and prolong flowering. Pinch early for bushiness.
Notes
The edible, citrus-scented marigold - finer-textured and more compact than T. erecta, with a tidy mounding habit ideal for borders and pots. Plant as a spring and fall annual in Tucson; like all marigolds it eases off in peak summer heat. Excellent low-water choice.
Sources: University of Arizona Cooperative Extension - Pima County Gardening Guides; Missouri Botanical Garden / Cornell horticulture references - Tagetes tenuifolia; Arizona Master Gardener annual flower references