Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
I used to be all about flowers. I thought that they were the only way to add color and interest to my gardens. Surprise, surprise. The foliage of plants like polka dot plants can also add color and interest to both your garden and indoors when grown as houseplants.
What is Polka Dot Plant?
Polka dot plant (Hypoestes phyllostachya) is an evergreen shrub that is native to Madgascar. It is grown for its colorful foliage. The plant is only perennial in zones 10 and 11. In colder regions, it is grown outdoors as a bedding annual or indoors as a houseplant.
Polka dot plant grows 1 – 2 feet tall and 1 foot wide. When grown as an annual, they tend to be much smaller. The leaves are the most striking thing about the plants. They are green with pink spots. Newer cultivars have leaves with white, red, rose or burgundy spots.
The flowers are what is known as insignificant. This means that they are not large and showy. They grow along a raceme which is a stalk. The flowers can be lilac, pink or blue. Bloom time is late summer or early fall.
How to Grow Polka Dot Plants Outdoors
You will most often see polka dot plants being used as a bedding plant in outdoor gardens. Plant them in the spring after your last frost when temperatures have reached 70⁰F and the soil has warmed. In my zone 6 NJ garden, that’s generally the last week in May or first week in June.
They like semi-shade so they are perfect to brighten up a shady spot in your yard. They can also be grown in containers and window boxes. Try to shield them from afternoon sun. The colors in the leaves fade in too much sun. They will also fade in too much shade so don’t plant them in full shade areas.
Polka dot plants like rich, well-drained soil. Mix in a thick layer of compost when you install your plants in the spring. Water regularly, about 1 inch per week, so that the soil stays moist but not soggy. A thick layer of mulch will help the soil to retain water and prevent weeds from taking hold.
The plants will get leggy so it’s a good idea to pinch on a weekly basis. Pinching means removing the growing tip on the end of each stem. When you remove the growing tip, instead of stopping the plant from growing, the plant grows two or more new growing tips to replace the one you removed. This results in the plant having more stems so that they become bushy instead of having long spindly stems
How to Grow Polka Dot Plants Indoors
Because they like shade, polka dot plants make good houseplants. Our houses which seem so bright to us are actually shady for a plant’s point of view. That’s why most houseplants are shade plants in their native environment.
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You can grow your plant in regular potting soil. Make sure that your container has a drainage hole. Polka dot plants like their soil to be moist, not soggy. A good rule of thumb is to water your plant when the top inch of soil has become dry.
Polka dot plants like a humid environment. This is not a problem when the plants are growing outside, but indoors is different. Our homes are too dry for them. Mist your plants regularly or create a humidity tray. A humidity tray is simply a shallow pan filled with ornamental gravel. Fill the pan with water and place your plant on top of the gravel. As the water evaporates, it creates a humid environment. Another way to provide humidity for your plants is to place a bowl of water next to them. As the water evaporates from the bowl, it creates the humidity that the plants need.
When grown outdoors, polka dot plants need shade. Indoors, they can be grown in a sunny room with either an east or south facing window. If your plant is looking long and spindly, it probably isn’t getting enough light. Move it to a brighter window.
Fertilize your plant monthly with a fertilizer that is formulated for houseplants. Every time you water, the water leaches nutrients out of the soil and out the drainage soil. You need to replace those nutrients or your plant will die.
Pinch your plants if they get too leggy or spindly.
How to Grow Polka Dot Plants From Cuttings
Polka dot plants grow readily from cuttings. The best time to take cuttings is in the spring or summer when the plants are actively growing. Make a 4 – 5 inch cutting from a stem and remove the leaves from the bottom half. You can use rooting hormone if you wish but it is not necessary. Gently press the cutting into pre-moistened soil in a container. I like to water soil before I plant my cuttings because if I water afterwards, the soil and the cutting tend to float out of the container.
Keep the soil moist. Your cutting should start to grow roots in about a week. You can tell that it is growing roots because you will see new foliage. Plants without roots cannot grow new leaves.
How to Grow Polka Dot Plants From Seed
Polka dot plants can also be grown from seed. Start your seeds indoors 10 – 12 weeks before your last frost. Surface sow them on pre-moistened soil. Do not cover them. They need light to germinate. I like to water before I plant my seeds because if I water afterwards, both the soil and the seeds float out of the container.
Optimal temperature is 70⁰F to 75⁰F. A heat mat will quicken germination. Germination should occur in 1 – 2 weeks. Don’t be discouraged if the cotyledons are solid green. The cotyledons are the first leaves and will fall off once the true leaves start to grow. The true leaves will be the multi-colors that you are expecting.
You can transplant your seedlings outdoors after your last frost when air temperatures have reached 70⁰F and the soil has warmed.
© 2020 Caren White