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How to Grow: Four- O- Clocks
Learn how to grow Four O Clocks including information on varieties.
Listen to podcast:
Marvel of Peru
full sun, part sun, part shade
Bloom Period and Seasonal Color
Mid summer until frost in colors of yellow, pink, rose, salmon, white, red and striped
Mature Height x Spread
2 ft to 3 ft x 1 ft to 2 ft
Attracts hummingbirds, attracts beneficials, deer resistant
Four o clocks are bushy annuals with colorful flowers and a sweet lemon or orange fragrance. They grow equally well in part shade as well as full sun. They begin flowering in midsummer when sown directly as seed, but will flower earlier if grown as transplants. The individual flowers open in late afternoon, usually between 4 pm and 8 pm (hence the common name). I won’t set my watch by them, though. They often will stay open until the following morning, then close and die. This makes them great flowers to enjoy after work or first thing in the morning. Flowers may remain open all day on cloudy days. A single plant may contain different colored flowers depending on the mix.
When, Where, and How to Plant
Plant seeds directly into the soil after all danger of frost has passed in spring, around the time you plant tomatoes. Soak seeds overnight in warm water the night before planting to hasten germination. Grow four o clocks seedlings indoors under grow lights 6 to 8 weeks before your last frost date and transplant seedlings into the garden as well. Transplants will bloom earlier than direct seeded plants.
Plant in a full sun or part shaded bed in well-drained, compost-amended soil. Sow seeds or transplant seedlings 1 to 2 feet apart. You can also grow four o clocks in 1 to 5 gallon-sized pots growing 2 to 5 plants per pot depending on the pot size. Keep the containers well watered and fertilized monthly.
Keep plants well watered and weeded. Fertilize in mid summer with an organic plant food to spur more growth and flowering. Fertilize more often for plants growing in container.
Regional Advice and Care
Pinch back the main shoot when the transplant is young to promote a bushier plant and more flowering
Four o clocks are perennial flowers in warmer climates and produce underground tubers that will overwinter. In New England the tubers die with the winter’s cold, but the seeds that drop from spent flowers will survive in the ground and sprout in your garden next year. Collect the black seeds after the flowers have passed in fall to sow in your garden next spring or thin out self-sown seedlings the following year.
Companion Planting and Design
Grow four o clocks in flower garden, along walkways and in containers in decks and patios to enjoy the fragrance. Four o clocks add color to a part shade garden and can get quite bushy by fall. Grow four o clocks to add color to a partly shaded hosta bed and a low growing shrub border.
While you can buy four-o-clock varieties in single colors, I like the ‘Marbles Mix’ with an assortment of striped, flower colors. Another favorite is the eye-catching ‘Limelight’ featuring lime green leaves and fuchsia colored flowers.
Excerpted from my book, New England Getting Started Garden Guide.
There’s an old fashioned flower that I have taken a liking to over the past few years. It’s an odd bird. It has different colored blossoms on the same plant. The flowers open in late afternoon and close in the morning. It goes by the common name the Marvel of Peru, since it hales from the Andes Mountains, but we mostly know it as 4 o clocks.
Not only do I like the odd flowering cycle and colorful blooms of 4 o clocks, the fragrance is intoxicating, attracting hummingbirds and bees. 4 o clocks are easy to grow, direct seeding it now. It grows into a 1 to 2 foot tall and wide shrub by mid summer and blooms its little head off. Eventually it forms a black, carrot-like tuber that can be dug in fall and stored in winter like dahlias, to be replanted in spring. They also can self sow.
Although they can take some shade, 4 o clocks flower best in full sun on well-drained soil. Some people may get a rash from rubbing the leaves, so wear gloves and a long sleeved shirt when working the plant. The seeds also can be toxic if ingested. Most varieties have multiple colored flowers on the same plant. These include, white, pink, yellow, red, and bicolor blooms. ‘Limelight’ is a newer variety with fuchsia colored flowers and lime green leaves that offer a bright color even when not in bloom. Plant 4 o clocks in a container or near a window where you can enjoy the fragrance in the evening. You can also have some fun creating a flower clock. Plant morning glories, daylilies, 4 o clocks, and moonflowers in one bed. When in bloom, the flowers will open in that order starting in the morning until evening.
From the Vermont Garden Journal on Vermont Public Radio.