How to Grow and Care for Popcorn Plants

The popcorn plant (Senna didymobotrya) is a tall shrub, and in its native African habitat, it can grow up to 25 feet in height. When grown in colder climates as an annual, it usually doesn't get taller than 3 feet. The plant's common name comes, in part, from its distinctive scent, said to be uncannily like buttered popcorn. The smell comes not from the racemes of 20 to 30 bright yellow flowers (which also look a bit like popped popcorn) but from the small oval leaves. The bright green, leathery leaves grow to about 3 inches long in pairs up and down the stem. The plant is popular with children for its recognizable scent that must be coaxed by touching the leaves. However, since the plant is toxic if ingested, it's best not to have it in reach of small children or curious pets.

Popcorn Plant Care

Here are the main care requirements for growing popcorn plants:

• Plant in rich, fertile, well-draining soil in direct sun.
• Thrives in hot climates as it is a heat-tolerant species, well suited to humid regions.
• Water and fertilize regularly throughout the growing season.
  

Warning

Senna pendula (Climbing cassia) is another senna species that can become invasive in hot humid regions such as south Florida. Check the label to be sure that you are indeed planting Senna didymobotrya.

Light

The popcorn plant likes heat and light, so it's best to place your plants in direct sun. If the plant is getting too hot and dry, its leaves may close up during the day. They also tend to close up at night to conserve moisture.

Soil

This plant likes very fertile, rich, and well-drained soils. When grown in pots, potting mix with some sandy loam is a good combination. Potting mix alone may drain quickly and leave this moisture-loving plant too dry.

Water

Water your tropical popcorn plant regularly. Daily is the best bet if it's in a container. If the leaves close up during the day, that means it may be wanting some water. Keep the soil moist but not wet. Misting the leaves with water in a sprayer is advisable if the weather is hot and dry.

Temperature and Humidity

After daily temperatures fall below 80 degrees Fahrenheit, the flowering and growth of your popcorn plants will slow down somewhat. This plant adores high humidity levels.

Fertilizer

Popcorn plants respond well to fertilizer throughout the growing season. Fertilize in late spring and again once or twice in middle and/or late summer with a fertilizer designed specifically for tropical plants. For the amount to use, follow the product label instructions.

Pruning

Deadheading spent blooms and trimming any dead or leafless branches will help to keep your popcorn plant looking healthy and full. There's no need for serious pruning.

Propagating Popcorn Plants

The plant is offered as a fairly inexpensive annual at garden centers so propagating your own might not be worth the effort. Growing the plant from cuttings can take a long while and is often unsuccessful, which is why propagating via seed is usually the best bet.

How to Grow Popcorn Plants From Seed

In late fall, you can pull the dried seed pods from an existing plant. The seed pods are several inches long and contain at least a dozen seeds each.

1. Start the seeds in very early spring with the goal of planting healthy seedlings in the garden after all threats of frost have passed. Soak the seeds in water for 24 hours.
2. Sow seeds in containers filled with well-draining yet moist potting soil and only cover it with a dusting of soil. Place it in a bright, warm location and keep it evenly moist.
3. Harden off the seedlings before planting them outside.

Potting and Repotting Popcorn Plants

When growing these plants in containers, make sure the soil is well-draining, and ensure plenty of drainage holes in the bottom of the container. Terracotta is an excellent choice as its porous walls allow moisture to evaporate. It can also help to add a layer of pebbles to allow the water to drain even further. The container should be at least a few inches wider than the roots of the plant to allow for space to grow, as well as wide enough to handle the height of the growing plant without allowing it to topple over.

To plant it outdoors, wait until all danger of spring frost has passed.

Overwintering

Popcorn plants can be overwintered if kept indoors. A greenhouse is preferable, but a garage is fine if the temperature stays above 40 degrees Fahrenheit. They will only need watering occasionally.

If kept in a dark place the plant will go dormant. Bring it back outside once all danger of frost has passed and the nighttime temps stay above 40 degrees Fahrenheit on a regular basis.

If you are in a tropical zone, overwintering plants in the garden should not be an issue.

Common Pests and Plant Diseases

Fortunately, this plant doesn't have much trouble with pests or diseases. Aphids will sometimes sample it; they can be remedied by a strong jet of water to wash them away or horticultural oil to deter them. This plant can also experience fungal diseases if kept too wet. Avoid this by giving it excellent air circulation and keeping the soil moist, but not wet.

How to Get Popcorn Plants to Bloom

With proper care, plenty of water, and good fertilizer, popcorn plants will bloom all summer long and into the autumn but will be at their most floriferous in the hot humid days of summer. Popcorn plants should bloom readily in their proper climate zone. When other plants wilt in the heat, the popcorn plant flourishes. As a tropical plant, blooms can be severely stunted if the temperatures drop below 40 degrees Fahrenheit. After flowering for a long season, the plant puts out brown seed pods.

Bloom Months

Popcorn plants typically bloom in late summer into fall, between July and September.

What Does Popcorn Plants' Flowers Look and Smell Like?

The popcorn plant's vibrant color—yellow—makes it a dramatic sight in the summertime garden landscape. Many say their scent is extremely similar to buttered popcorn.

How to Encourage More Blooms

To keep it blooming well, make sure it's inside and protected during the colder months. A popcorn plant that is kept in the garden soil will die back if the winters are too cold and will need to be replaced in the spring.

From: thespruce