How to Grow Four O’Clocks
Looking for a flower that blooms through the hottest months of summer? Four o’clocks are one of my favorite heat-loving flowers. They bring bright color, attract pollinators, and keep blooming when many other flowers struggle in the heat.
I first saw four o’clocks on a list of flowers that bloom through Arizona summers. I didn’t know how to grow four o’clocks, but I figured that if they could thrive in the low desert, they were worth trying.
The list was right. I planted four o’clock seeds and was rewarded with beautiful blooms from mid-summer until temperatures cooled in the fall. I now plant them each summer and enjoy the bright colors and pollinators they bring to the garden.
Key Takeaways: How to Grow Four O’Clocks
- Four o’clocks thrive in heat, bloom from mid-summer to fall, and attract pollinators.
- To grow four o’clocks, plant seeds directly in well-draining, compost-rich soil with plenty of sunlight.
- Timing is key: plant four o’clocks around the same time as tomatoes for best results.
- Care for them by keeping the soil moist; feeding is optional for more blooms.
- Save seeds or bulbs for the next season, but remember that all parts of the plant are toxic.
Why You’ll Love Four O’Clocks
Four o’clocks are one of the easiest flowers to grow for summer color. These old-fashioned favorites thrive in hot weather and reward gardeners with months of blooms when many other flowers are struggling.
Here are a few reasons to love four o’clocks:
- Bloom through the heat. Four o’clocks flower from mid-summer until temperatures cool in fall, even during Arizona’s hottest months.
- Attract pollinators. Bees, butterflies, hummingbirds, and other beneficial visitors are drawn to the colorful, trumpet-shaped blooms.
- Easy to grow from seed. Four o’clocks germinate readily and grow quickly, making them a great choice for beginning gardeners.
- Beautiful colors and patterns. Flowers bloom in shades of pink, yellow, red, white, and magenta. Some plants even produce different-colored flowers on the same plant.
- Fragrant evening blooms. The flowers have a sweet fragrance that is especially noticeable in the evening.
- They come back year after year. In warm climates, four o’clocks often reseed themselves and may return from their tuberous roots. Find more perennials that attract pollinators here.
Why Are They Called Four O’Clocks?
Four o’clocks earned their name because their flowers typically open in the late afternoon and remain open through the night until the following morning. During especially hot weather, the blooms may wait until evening to open. Watching the flowers unfold each afternoon is part of their charm.
5 Tips for Growing Four O’Clocks
1. Sow Four O’Clock Seeds Directly in the Garden
Four o’clocks are easy to grow from seed and are best planted directly in the garden after the danger of frost has passed. The large black seeds germinate readily and grow quickly once temperatures warm.
Native to tropical regions of North and South America, four o’clocks are perennial in frost-free climates but are often grown as annuals in much of the United States.
One of the most popular varieties is ‘Marvel of Peru,’ which produces blooms in shades of pink, red, yellow, and white. Some plants even display multiple flower colors at the same time, adding extra interest to the garden.
2. Choose the Best Location for Growing Four O’Clocks
Four o’clocks grow best in well-draining, compost-rich soil and thrive in locations that receive plenty of sunlight. Find my perfect soil recipe here. They can also tolerate partial shade. In hot climates like the low desert of Arizona, afternoon shade helps plants look their best during the hottest months of the year.
Before planting, be sure to give four o’clocks enough room to grow. Mature plants often reach 2–3 feet (0.6-0.9 m) tall and 1–2 feet (0.3-0.6 m) wide. The branches can become brittle as plants grow larger, so providing support may help keep plants upright.
My favorite place to grow four o’clocks is at the corners of raised beds. I tuck a seed or two into each corner and let the plants spill over the sides, adding color without taking up valuable growing space. Four o’clocks also work well as border plants and are a great choice for containers. Learn how to plant crops in containers in this guide.
3. Plant Four O’Clocks at the Right Time
Four o’clocks grow best when planted in warm soil. A good rule of thumb is to sow seeds around the same time you plant tomatoes. Waiting until the soil has warmed helps seeds germinate quickly and plants establish well.
In the low desert of Arizona, plant four o’clock seeds from March through June. Depending on planting time, you can expect blooms from mid-summer through fall, often continuing until temperatures cool in November.
Be sure to give plants enough room to mature. Four o’clocks can grow surprisingly large during the summer. If you’re using the Square Foot Gardening method, allow about 2 square feet (0.6 m) per plant.
The Perpetual Annual Flower Planting Calendar, available in my shop, helps you learn when to plant flowers in the low desert of Arizona and whether to plant seeds or transplants.
4. Care for Four O’Clocks as They Grow
One of the best things about growing four o’clocks is how little maintenance they require. Once established, they are easy-care plants that reward busy gardeners with months of colorful blooms.
Provide regular water and keep the soil evenly moist, especially during hot weather. A layer of mulch can help retain moisture and keep roots cooler during the summer. Here’s my favorite way to evenly water my garden beds.
Four o’clocks generally grow well without much attention. Feeding plants throughout the growing season may encourage additional blooms, but fertilizing isn’t necessary for healthy growth and flowering. When I do feed them, I use this fertilizer.
5. Save Seeds or “Bulbs” for Next Year
Four o’clocks are easy to grow again the following season. After flowering, plants produce large black seeds that are simple to collect and save. Allow the seeds to mature and dry on the plant before harvesting them. In many gardens, seeds will also drop naturally and self-seed, resulting in new plants the following year.
In addition to producing seeds, four o’clocks develop large tuberous roots that resemble small potatoes. In mild-winter climates, these roots can be left in the ground and will often return year after year. Gardeners in colder climates can lift the tubers after frost, store them in a cool, dry location, and replant them in spring.
Important: All parts of four o’clock plants, including the seeds and tuberous roots, are considered toxic if ingested. Plant them in an area where children and pets will not be tempted to eat them.
how do you store the seeds and the bulb root for next season planting
generally you store seeds in a cool, dry place. I usually put them in a paper sack until I make sure they are completely dry. Bulbs would be in a cool dry place as well.