Learn About Four O Clocks
How to Sow
How to Sow and Plant
Four O’Clocks may be grown from seed sown early indoors and transplanted outside after frost, or sown directly in the garden after frost.
Sowing Seed Indoors:
- Sow indoors 6-8 weeks before frost in spring using a seed starting kit
- Sow evenly and thinly and cover with ½ inch of seed starting formula.
- Firm lightly and keep evenly moist.
- Seedlings emerge in 7-10 days
- As soon as seedlings emerge, provide plenty of light on a sunny windowsill or grow seedlings 3-4 inches beneath fluorescent plant lights turned on 16 hours per day, off for 8 hours at night. Raise the lights as the plants grow taller. Incandescent bulbs will not work for this process because they will get too hot. Most plants require a dark period to grow, do not leave lights on for 24 hours.
- Thin to one seedling per cell when they have two sets of leaves.
- Seedlings do not need much fertilizer, feed when they are 3-4 weeks old using a starter solution (half strength of a complete indoor houseplant food) according to manufacturer’s directions.
- Before planting in the garden, seedling plants need to be “hardened off”. Accustom young plants to outdoor conditions by moving them to a sheltered place outside for a week. Be sure to protect them from wind and hot sun at first. If frost threatens at night, cover or bring containers indoors, then take them out again in the morning. This hardening off process toughens the plant’s cell structure and reduces transplant shock and scalding.
Sowing Directly in the Garden:
- Direct sow seeds in average soil in full sun after all danger of frost.
- Prepare the soil by removing weeds and working organic matter into the top 6-8 inches of soil; then level and smooth.
- Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
- Sow seeds about 6 inches apart and cover with ½ inch of fine soil.
- Firm soil lightly with your hand, water and keep evenly moist.
- Seedlings will emerge in 7-10 days.
- Thin to stand 12-18 inches apart when seedlings are 1-2 inches high.
How to Grow
- Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their seeds from germinating.
- Mulches also help retain soil moisture and maintain even soil temperatures. For annuals an organic mulch of shredded leaves lends a natural look to the bed and will improve the soil as it breaks down in time. Always keep mulches off a plant’s stems to prevent possible rot.
- Plants need about 1 inch of rain per week during the growing season. Use a rain gauge to check to see if you need to add water. It's best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
- Until plants become established, some protection from extreme winds and direct, hot sunlight may be necessary. Good air movement is also important.
- After new growth appears, a light fertilizer may be applied. Keep granular fertilizers away from the plant crown and foliage to avoid burn injury. Four O’Clocks tend to prefer poor soils so do not overfertilize.
- Remove spent flower heads to keep plants flowering until fall. Leave some on at the end of the season to allow the plant to self-sow.
- Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
- Four O’Clock flowers only open in the afternoon, around 4:00. They make poor cut flowers because they may not remain open.
- Good for children to grow, since they are colorful, easy to plant, and fast growing.
- Plants often self-sow, so allow some spent flowers to go to seed.
- The roots form tubers that may be dug up and stored over the winter.
- Shorter varieties are fine for containers.
- Plants are heat and drought tolerant.
Common Pests and Problems
Cercospora Leaf Blight: Small flecks which develop a yellowish halo appear on the leaves and turn brown and coalesce. They cause the leaves to wither and die. Burpee Recommends: Remove infected plants and destroy all plant debris. Rotate crops.
Fusarium Wilt: The first symptom of fusarium is the appearance of a few yellow leaves or a slight drooping of the lower leaves. Caused by a soil-borne fungus, the fungus enters through the roots and passes up into the stem producing toxic substances. Burpee Recommends: Destroy affected plants at the first sign of fusarium; rotate crops.
Root Rots: A number of pathogens cause root rots of seedlings as well as mature roots. Burpee Recommends: Pull up and discard infected plants. Make sure your soil has excellent drainage. Contact your Cooperative Extension Service for recommendations.
Rust: A number of fungus diseases that cause rust colored spots on foliage and stalks. White rust causes branches and leaves to swell; raised pustules can form on the front as well as the back of leaves. Branches may be deformed, erect and spindly. Burpee Recommends: Remove infected plants. Contact your Cooperative Extension Service for recommendations.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Are Four O’Clocks annuals or perennials? Mine keep coming back! Four O’Clocks are tender perennials which may be overwintered as dormant roots indoors over the winter. They can also self-sow, which may be what happened if you did not dig them up.
Can you grow Four O’Clocks in containers? Some varieties are rather large and do not do well in containers, but smaller varieties are available. Be mindful that they will not bloom until late afternoon when you site the containers.
Are Four O’Clocks deer resistant? Yes, they do tend to be deer resistant.
Do Four O’Clocks attract pollinators? Yes they attract butterflies and hummingbirds.