How to Plant Four O’Clock Tubers


Four o’clocks are delightful perennial growing flowering plants that grow from thick tuberous roots. Originally from areas in South American, four o’clocks have become naturalized in milder climates throughout the western hemisphere. Also known as beauty-of-the-night and marvel of Peru in various regions of the world, they are hardy in the USDA Zones 7 to 11. In colder climates they are typically raised as annuals since they cannot abide an abundance of frosty cold weather. You can plant four o’clocks from tubers in spring as soon as no further chance of freezing weather is expected.

Difficulty: Moderately Easy


Things You’ll Need:

  • Four o’clock tubers
  • Rototiller
  • Amendment
  • Measuring tape
  • Planting stakes
  • Fertilizer
  1. Locate a suitable site for the four o’clock tubers. The site should be in full sun otherwise flowering will be greatly reduced. Since four o’clocks produce some garden litter, avoid planting near pools or sidewalks.

  2. Rototill the area to a depth of between 18 and 24 inches. Pick out any large debris such as roots, rocks and clumps of vegetation as your till the soil. You can also use a shovel, or pick if you do not have the use of a rototiller.

  3. Incorporate into the soil a 3 or 4 inch layer of organic matter to enrich the soil and improve drainage. Use compost, aged steer manure or any other similar material.

  4. Dig holes for each tuber that are approximately 1 1/2-inches deeper (or longer) than each of the tubers. Each hole should be wide enough to accommodate the approximate width of each tuber. Space each hole about 2 feet apart to allow plenty of room for the four o’clocks to grow.

  5. Plant one four o’clock tuber into each planting hole. Plant with the rounded root side down, and the pointed end facing up.

  6. Cover all the four o’clock tubers with about 1-inch of soil. Tamp the soil down over the tubers.

  7. Push in 12-inch tall planting stakes about 4 to 6 inches away from each tuber you planted so you will know where to water and to avoid walking. Depending on the soil and air temperature, the tubers may begin sprouting in 4 to 6 weeks, or sooner.

  8. Water the four o’clock tubers with a generous amount of water. You can use a sprinkler head attached to a garden hose. Let the water run for 10 to 15 minutes or however long it takes to soak the area. For the first week (depending on the weather) water once a day then reduce watering to 2 to 3 times a week until established.

Tips & Warnings

  • Begin fertilizing four o’clocks about once every 4 to 6 weeks as soon as you see the tubers sprouting. Use either a liquid soluble fertilizer or granular type fertilizer such as 12-12-12. Spread rates depend on the individual manufacturers suggestions so be sure to read the directions that are provided on the products label.

  • If you do not wish to have the four o’clocks self-seed, cut back the plants about 10 days after blossoms fade.

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