Nyctaginaceae
Sweet Four O'Clock (Mirabilis longiflora)
Mirabilis longiflora
Give it full sun, well-draining soil, and let the soil dry between waterings. It dies back to its tuberous root at the first frost and re-sprouts in spring, needing little more than occasional deadheading and a light feed during the growing season.
Every 7 days
Bright indirect
° - °C
% - %
Categories
What is Sweet Four O'Clock?
Sweet Four O'Clock (Mirabilis longiflora) is a easy-care plant from the Nyctaginaceae family. Mirabilis longiflora, the sweet four o'clock, is a tuberous perennial native to the scrubby canyons and riverbanks of the southwestern United States and northern Mexico. It produces long, slender white-to-pink tubular flowers with a purplish throat that open at dusk and release a sweet, orange-bloss...
Sweet Four O'Clock grows up to 1.5m, spread of 90cm, watering every 7 days. It is not suitable for indoor environments and not safe for pets.
Unlike many tropical plants, Sweet Four O'Clock tolerates watering mistakes. Best for beginners. Without precautions, ingestion can cause irritation in pets. Keep out of reach of cats and dogs.
How to Care for Sweet Four O'Clock?
TLDR: Sweet Four O'Clock needs Bright indirect, watering every 7 days, and temperatures between 15-30°C with 40-70% humidity.
How Often Should You Water Sweet Four O'Clock?
Water deeply but infrequently, letting the top few centimeters of soil dry out between waterings; this drought-tolerant perennial is far more likely to suffer from root rot than from underwatering.
How Much Light Does Sweet Four O'Clock Need?
Plant in full sun for the heaviest bloom; in very hot climates, afternoon shade helps prevent leaf scorch.
What Is the Best Soil for Sweet Four O'Clock?
Use loose, well-draining soil enriched with compost; heavy, waterlogged soil quickly leads to tuber and root rot.
What Pot Should You Use for Sweet Four O'Clock?
A wide terracotta or unglazed clay pot with generous drainage holes suits its tuberous roots and helps excess moisture evaporate.
Care Schedule
Fertilize
Every 30 days
What Is Sweet Four O'Clock and Where Does It Come From?
Mirabilis longiflora, the sweet four o'clock, is a tuberous perennial native to the scrubby canyons and riverbanks of the southwestern United States and northern Mexico. It produces long, slender white-to-pink tubular flowers with a purplish throat that open at dusk and release a sweet, orange-blossom-like fragrance through the night.
How to Propagate Sweet Four O'Clock?
Seed sowing
Self-seeds readily in warm climates; thin seedlings to 45-60cm apart for healthy growth.
- 1 Soak seeds in water for 24 hours before sowing.
- 2 Sow directly in the garden after the last frost, or start indoors 6-8 weeks earlier.
- 3 Keep soil moist at 13-18C (55-65F) until germination.
- 4 Transplant seedlings outdoors once frost danger has passed.
Materials needed:
Tuber division
Handle tubers with gloves - all parts of the plant are toxic if ingested.
- 1 In early spring, carefully dig up the fleshy tuberous root.
- 2 Cut the tuber into sections, ensuring each piece has at least one growth bud.
- 3 Let cut surfaces callus for a day before planting.
- 4 Replant divisions at the same depth in well-draining soil and water well.
Materials needed:
How Big Does Sweet Four O'Clock Grow?
TLDR: Sweet Four O'Clock can reach up to 1.5m tall with Medium growth rate.
Max height
1.5m
Spread
90cm
Growth rate
Medium
Foliage
Deciduous
Warning: Toxic Plant
This plant can be toxic if ingested. Keep out of reach of:
Plant Uses
Ornamental
Great for decoration
Aromatic
Pleasant fragrance
Is your plant showing symptoms?
Click on the symptom to discover possible causes:
What Diseases Commonly Affect Sweet Four O'Clock?
TLDR: Sweet Four O'Clock is susceptible to 5 known diseases. Monitor regularly for early detection.
Aphids
Aphids are small, soft-bodied, pear-shaped insects (1/16 to 1/8 inch long) that feed by sucking nutrient-rich sap from plants. They reproduce rapidly and can quickly weaken plants, causing distorted growth and transmitting plant viruses. Aphids come in various colors including green, black, red, yellow, brown, and gray. They secrete honeydew, a sticky substance that attracts ants and encourages sooty mold growth.
Spider Mites
Spider mites are tiny arachnids (less than 1/20 inch long) related to spiders and ticks that feed on plant sap. They thrive in hot, dry conditions and can cause significant damage to ornamental and vegetable plants. During severe infestations, crop losses can reach 14% or higher as these pests disrupt vital plant processes including photosynthesis, carbon dioxide absorption, and transpiration.
Powdery Mildew
Powdery mildew is a common fungal disease caused by various fungi species including Erysiphe, Podosphaera, Oïdium, and Leveillula. It affects over 10,000 plant species worldwide. The disease thrives in warm, dry climates with high humidity and appears as a distinctive white powdery coating on plant surfaces.
Root Rot
Root rot is a serious fungal disease that affects the root system of plants, causing them to decay and die. It is primarily caused by overwatering, poor drainage, or soil-borne fungi such as Pythium, Phytophthora, Rhizoctonia, and Fusarium. The disease thrives in waterlogged conditions where roots are deprived of oxygen, making them susceptible to fungal infection.
Meaning & Symbolism
As a night-blooming flower that releases its fragrance after dusk, it is often associated with mystery, hidden beauty, and the quiet magic of the evening garden.
Fun Facts
Its trumpet-shaped flowers can reach up to 17 cm long, among the longest in the four o'clock family.
Flowers open in the late afternoon and stay open through the night, closing again by mid-morning.
It is pollinated almost exclusively by hawkmoths (sphinx moths) drawn to its sweet, orange-blossom scent.
Despite dying back completely after the first frost, its fleshy tuberous root can survive underground and resprout for years.
Frequently asked questions
Is Mirabilis longiflora toxic to pets?
How often should I water sweet four o'clock?
Why does Mirabilis longiflora only open its flowers at night?
Does sweet four o'clock come back every year?
Compare with similar plants
| Attribute | Difficulty | Light | Watering | Pet Safe |
|---|---|---|---|---|
| Field Maple | Easy | Bright indirect | 14d | ✓ |
| Silver Birch | Easy | Direct sun | 14d | ✓ |
| Bougainvillea | Medium | Direct sun | 7d | ⚠️ |
| Common Blanketflower | Easy | Direct sun | 10d | ✓ |
