Wax Begonia (Begonia Semperflorens) Plant Care Guide

Last Updated on April 18, 2022 by Admin

Wax begonia (Begonia Semperflorens) are very popular because of their blooming ability, durability and good looks. As such, they’re often used in garden beds. You also get a wide variety.

As such, there are lots of colors to choose from including pink, yellow and white. Some, but not all varieties are fragrant as well.

Table of Contents

Wax Begonia Plant Care

Wax Begonia Light

Wax begonia are often grown outdoors. But, they’re great as houseplant too.

Whichever way you decide to keep them, the most important thing to remember is they thrive of full sun. The more bright light, the better.

The only exception here is when the weather is overly hot and scorching and the sun is very intense. In these conditions, it will appreciate a little bit of shade or filtered light.

This makes it very easy to grow outdoors as long as you have access to at least 6 to 8 hours of sunlight daily.

But, it can be more of an issue indoors, if you don’t have access to a bright window.

What all this means is that if you notice that your wax begonia is not flowering as well as it should, give it more sun.. The only exception is if it already in under very hot sunlight on a daily basis. If that’s the case scale back a bit.

Interestingly, given direct sunlight causes its leaves to be smaller than they would be when under some kind of shade.

So, you may want to experiment a little to see what balance of foliage and blooms you want based on the amount of sunlight it receives.

Wax Begonia Temperature & Humidity

Your wax begonia enjoys warm conditions. And, it is very happy when the temperature stays between 60 and 75 degrees Fahrenheit.

As such, it doesn’t have a problem with indoor temperature as long as you keep it away from cold drafts and breezes. So, air conditioning and other vents are no-no’s.

It also means that the plant can be grown as a perennial in USDA zones 8 to 11. If you live in these regions, you can plant it outdoors, be it in your garden or keep it in a container in your deck or patio.

However, overly high temperatures can cause its buds to drop. As such, it is a good idea to give it a little shade during the hottest months of the year.

In other parts of the country, it will survive as an annual. Most gardeners here will keep them in pots so they can bring them indoors before first frost.

Others grow them as houseplants. The biggest advantage of this is that if you keep it in a bright windowsill with lots of sunlight, you’ll be able to enjoy its blooms for much longer than just the summer.

That said, the plant is not frost hardy. Nor can it tolerate freezing temperatures.

So, once the mercury drops in mid fall below 50 degrees, if you keep the plant outside, you’ll need to move it somewhere warmer for the winter.

Your wax begonia is not fussy about humidity. So, it will be happy with regular room temperature humidity or that in the outdoors.

Wax Begonia Watering

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Wax begonia enjoy moist soil but don’t like wet feet. So, it is a good idea to allow the soil to dry between watering sessions. However, the plant can only tolerate short, mild periods of drought. So, you don’t want to leave it dehydrated for too long.

Younger wax begonia need more water to fuel their faster growth. But, once they’re established, they don’t need as much water.

This means that when it comes to moisture, the safer side is less water. That’s because overwatering or poor draining soil can quickly lead to root rot.

A good way to tell when it is time to water is to feel the soil at an inch below the surface. At this depth, if the soil feels dry, it is time to water. If the soil there is still moist hold off and check back in 1 to 2 days.

As such, following a very regular watering schedule is a bad idea. Since the weather changes through the year. And, the plant is actively growing during spring and summer, it will need more hydration.

On the other hand, as the weather cools down and goes to freezing, the plant transitions from active growth to resting stage. This means by mid to late fall, it won’t need much water anymore. And, the reverse is true in the weeks leading up to summer.

Just as important as knowing when to water, is how to water.

The best way to water your wax begonia is to place the hose or spout on the soil under the leaves. This waters the soil directly without wetting the leaves.

Water thoroughly until you see liquid start dripping out of the holes at the bottom of the pot, then stop.

At this point, allow the excess water to drain completely. You need to be patient here because it can take up to 15 minutes for larger containers. I like to do something else during this time.

Once the excess moisture has drained, you can return the pot the its spot.

While this takes a little longer than just spraying your plants from overhead with a hose, it prevents powdery mildew and fungal infections. It also eliminates the risk of letting the plant sit in water for a long time.

The combination of overwatering and poor soil drainage is a recipe for disaster. So, you want to aovid this.

Soil

From above, you already know that wax begonias like soil that’s able to retain some moisture. But, not too much that it becomes wet or soggy.

As such, the best soil for it is something that is light, airy and well-draining. This allows enough air pockets for water and oxygen to penetrate through the soil.

In doing so, it keeps the water from clogging all the air pockets. This also makes it easy for the liquid, fertilizer and oxygen to reach the roots.

As such, regular potting mix with either perlite or back chips added to it for extra drainage works well.

Outdoors, adding compost helps as it loosens the soil and adds organic matter. If your garden soil is on the heavier side, you can likewise add perlite, bark chips or coarse sand to improve drainage.

Wax begonia aren’t overly fussy above soil pH. As long as it is a little big acidic, it will be happy.

You can add peat to your soil is you want to increase acidity by a little. Plus, its water retention feature helps keep the soil moist as well.

In the summer, it is likewise a good idea to add mulch. This will protect your plant’s roots and prevent moisture from drying out too quickly especially in hot weather.

Fertilizing

Wax begonia only need light feeding. As such, you can use a balanced fertilizer diluted to half strength once a month during its growing season.

If you want to boost flower production, you use a high phosphorus fertilizer every third feeding in place of the balanced on. This nutrient helps blooming.

In the winter, stop feeding the plant even it is still growing.

Just like water, it is very important to avoid overfeeding. This can lead to fertilizer burn which damages its roots.

As such, some growers start with compost which increases organic matter in the soil. This reduces the need of fertilizing. It also allows them to use quarter strength each time.

Since fertilizer residue that accumulates in the soil isn’t good for your plant’s roots, you want to flush the soil every so often. It the word flush seems daunting it isn’t.

It simply means running extra water to through the soil for about a minute to minute an a half. This will cause the pot the leak liquid. But, it will also flush out the fertilizer salts and other minerals that have built up over time.

Pruning Wax Begonia

Wax begonia are low maintenance when it comes to pruning. As such, you get the best of both worlds.

Grown outdoors they will bloom profusely from spring all the way to late fall. Indoors as houseplants, you’ll be able to enjoy their blooms all year round provided that you give them good lighting.

Just as importantly, you don’t need to deadhead faded flowers. These plants are self-shedding. And, they don’t miss a beat in flower production while doing so.

The only little pruning that you’ll need to do is remove dead or damaged foliage. You’ll likewise want to trim off leggy stems.

Although, pinching is more effective as it encourages new growth and causes your plant to look fuller and bushier.

To do so, cut an inch above the leaf node.

Propagation

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Wax begonia can be propagated from seed or stem cuttings. Of the two, the latter is more efficient because it takes less time to grow them from cuttings. It is also more reliable of the two.

Snice these plants only last from 4 to 5 years, propagation is a good way of “extending” its life as the cuttings are from the original plant.

It is likewise a cost efficient means of growing more of it at home or for your garden.

Hot to Propagate Wax Begonia from Stem Cuttings

Spring is the best time to grow wax begonia from stem cuttings. Here’s how to do it step by step.

Take a healthy non-flowering stem that has a least 2 leaves.
You want to make the cut about quarter to half an inch below the leaf node.
Remove the lower leaves since you’ll be dipping the bottom end of the stem in water or soil.
Now you have a choice. You can root it in water or go straight to soil. The former allows the plant to root slightly faster. And, often has better success rates. But, it also runs the risk of root rot since the plant is left in water 24 hours for about a week. Once it roots, you can transfer the stem cutting to soil. Going straight to potting soil skips this step.
Before you put it in soil, make sure to use well draining soil. You’ll start with a smaller pot as well.
Plant the stem cutting into the soil.
Water and keep it moist.
Keep the pot in a warm, humid place where it receives bright, indirect light.
In about 1 to 2 weeks it should begin to root.
After a month or so, move it to a larger pot.

Wax Begonia Transplanting & Repotting

Wax begonia will eventually grow to about 18 inches high depending on the variety you have. It will likewise expand and get denser as it grows into a shrub.

The plant also enjoys being slightly pot bound. During this time, you’ll notice it flower very well. As such, there’s no need to hurry.

The only time you’ll need to repot is when you’re watering more than once a week and the roots are overtaking the pot. As the roots get bigger, the soil and the water is holds becomes insufficient for it. As such, it dries up fairly quickly.

All these factors put together, plus the fact that wax begonias live up to 4 or 5 years means you’ll only need to repot it once or twice ever.

It also means it is a good idea to take cuttings and propagate the plant as it closes in on that age. That way, you have a new plant when it dies.

Spring is the best time to repot the plant. And when you do, you only want to go up 1 to 2 inches in pot size, not more. Over potting can stress the plant. It also increases the risk of overwatering.

Toxicity

Wax begonia are mildly toxic. They contain calcium oxalates which can cause diarrhea, mouth and throat irritation and vomiting. If consumed in large amounts in can cause kidney failure in animals. So, keep dogs, cats and horses away from it.

It isn’t as poisonous to humans. But, the sap can still cause irritation and other side effects. So, keep young kids away.

Interestingly, the flowers are not toxic and they’re actually used in some foods.

Pests and Diseases

Unlike many begonias, wax begonias are quite resistant to pests. Their thick leaves can withstand attacks from different creatures the most common of which are whiteflies and mealybugs. But, you can likewise wee spider mites, aphids and thrips come around once in a while.

Similarly, it is very important to keep the plant dry. It can experience powdery mildew because of high humidity. Also, overwatering will increase its risk of root rot.

As such, while the plant likes moist soil and good humidity, both can become causes of problems when it comes to diseases.