All hibiscus varieties bloom around mid to late summer, treating us to bold and beautiful flowers for around 3 to 4 weeks out of the year – but this is far too short a time to appreciate their splendor!
With consistent and appropriate care, every gardener can significantly extend the hibiscus plant’s blooming cycle. Here are 11 tips for success…
1. Fertilize Routinely
Hibiscus plants are exceptionally heavy feeders and will appreciate additional nutrients during their active growing season to provide them with abundant blooms.
- As fertilizer options go for hibiscus plants, you can choose to use a diluted liquid fertilizer, a slow-release granular fertilizer (this one is excellent), or you can add potassium-rich compost to your soil (the easiest choice if you’re growing hibiscus directly outdoors).
- Amy Andrychowicz of Get Busy Gardening recommends applying an organic water-soluble fertilizer like this one once a week during spring and summer (4 tbsp. per gallon of water), as this can be used on indoor and outdoor potted hibiscus and contains no synthetic chemicals that would otherwise hinder flower growth.
- Stop fertilizing indoor and outdoor plants over fall/winter as they need this dormant “shut-down” period to re-focus their energy from flowers to root growth.
2. Water Consistently
These plants crave water in their blooming stage, which can make over-watering far too easy to do.
But don’t worry – the weather and the feel of the soil will be your guide to creating (and sticking by) a good watering routine.
- Avid gardener Lisa from The Practical Planter advises watering your hibiscus daily in its first week after being planted/potted before “tapering off to twice a week after that. Continue using this twice-a-week ideal, aside from when there is rainfall, and switch back to daily watering if the weather turns notably hot and dry.”
- As tropical plants, hibiscus soil should remain moist but not soggy or dry, so when in doubt, stick your finger about 1-2 inches deep in the soil, and if it feels dry or barely moist, it’s time to water. If it feels evenly moist or wet, check back the following day. You can always use a soil moisture monitor too!
3. Provide Adequate Light
- Hibiscus plants need at least 6-8 hours of daily direct sunlight to produce buds, so they’ll need to be planted in a full-sun spot in your garden if you live in a mild spring/summer climate or in partial sun if you live in a bright, hot location.
- However, if you’re growing your hibiscus plants in containers as many growers choose to, you can position your pots in direct sun when it’s cooler and give them much-needed afternoon shade during heatwaves (or for those living in the hottest USDA grow zones).
- Hibiscus grown in low-light indoor settings will need the help of grow lights (be sure they are full-spectrum lights) to replicate the recommended 6-8 hours sun.
4. Maintain Proper Temperatures
- This plant blooms best when temperatures remain consistently between 60 and 90°F (16-32°C ), but it won’t tolerate temperatures below 32°F (0°C), so potted hibiscus will need to be moved indoors a week or so before the first frost date in your area.
- While indoors, try to keep plants isolated from temperature fluctuations (e.g. drafty doors/windows, radiators, AC/heating vents, etc.) and only move the plants back outside again once night temperatures remain reliably above 50°F (10°C).
5. Check Routinely for Pests and Diseases – Treat Promptly
Hibiscus can fall prey to many indoor and outdoor nasties, including the flower-hungry Japanese beetle, spider mites, mealybugs, thrips, whiteflies, and aphids.
If left unchecked, flowers can drop prematurely and young buds will fail to bloom altogether.
- Monitor your hibiscus leaves and flowers regularly to spot-treat the issue right away. In many cases, you can hand-pick the pests off by tapping leaves with a pencil and catching pests with a paper towel, or deter future visitors with an organic insecticidal spray that will kill bugs and larvae but leave your plant unharmed.
- As for disease, taking care to water your hibiscus much less in winter will prevent most fungal issues from taking hold. Routinely check foliage, and apply organic fungicide at the first signs of disease (wilting, black spots, white mold, etc.). This helpful page includes images of common hibiscus pests and diseases for easy identification.
6. Repot When Needed
Hibiscus should not be repotted randomly but only when completely necessary to avoid needless stress to foliage and bud development.
These are the tell-tale signs your plant needs repotting:
- The roots are coming through the drainage holes.
- Roots are circling around the soil and appear tightly packed together.
- It’s suddenly started losing a lot of leaves.
- The soil is drying out faster than usual.
Here’s a great step-by-step tutorial for repotting your hibiscus!
7. Prune Only in Early Spring
- In the same way that trimming your hair makes way for healthier new strands, your hibiscus will benefit from heavy pruning to promote healthy additional blooms – ideally in early spring (around March 1st) before blooming occurs.
- Use heavy-duty pruning shears for a clean cut, and prune back any dead or damaged branches and yellow stems, and deadhead faded flowers from the previous season.
8. Mulch To Retain Moisture
- To encourage a longer blooming season, it’s a good practice to add a 1-inch layer of mulch around the base of your indoor pant (or rake a 3-inch layer on your bed-planted hibiscus) to reduce moisture loss and improve soil fertility in winter and early spring.
- To prevent rot, just be sure that the mulch doesn’t touch the stem/trunk of your plant.
- Keep in mind that mulch consisting of compost and shredded leaves will break down quite rapidly in the soil and will need replenishing every year or so, while heavy bark mulch may take several years to break down.
9. Ensure Soil Is Healthy and Drains Quickly
Hibiscus plants prefer a light, well-draining soil that has ideally been enriched with organic matter such as vermicompost (earthworm waste) to deliver a double nutrient boost in addition to regular fertilizer feeds.
A 2009 study found that hibiscus grown with vermicompost resulted in much greater flower production!
- Amend heavier, compacted garden soils with a 1-3-inch layer of vermicompost. For potted hibiscus, Get Busy Gardening’s Amy Andrychowicz recommends a recipe of “2 parts Espoma Organic potting soil, 2 parts coco coir (coconut husk fiber), and 1 part perlite (lightweight volcanic rock).”
- The addition of vermicompost or coco coir/perlite respectively improves soil fertility and creates an airy, free-draining medium that holds on to sufficient moisture without overwhelming the hibiscus roots.
10. Check Soil pH
Hibiscus thrives in soil that sits somewhere between 6.5 and 6.8 on the pH scale (slightly acidic) as this mid-range grants them access to all available nutrients, prompting bigger, better blooms.
- Check the pH levels of both your container and garden-planted hibiscus, and amend accordingly. The Pennington Lawn & Garden company advises adding lime (ground limestone) to increase pH or adding soil sulfur to decrease – allowing 2 weeks for the newly amended soil to achieve the correct pH.
11. Make Sure Pot Is Not Too Deep
While a deep container sounds beneficial, planting your hibiscus in one will cause it to direct its energy into producing healthy far-spreading roots rather than foliage and show-stopping blooms.
- When it’s time to repot, opt for a container that is wider than it is deep (around 10 inches across will suffice for your first repot from the nursery container).
- After that, choose pots only 1-2 inches wider in diameter than the previous and so on.
TIP! Hibiscus can afford to be a little root-bound (coiling around the soil) and will actually bloom more profusely in these conditions according to the American Hibiscus Society! So hold off from repotting until absolutely necessary (re: Step #6).
You’ll know you’ve implemented the above care tips correctly for your hibiscus when you notice the individual flowers opening up for 2-3 days instead of the usual 24 hours and its overall blooming period beginning earlier in mid-spring and lasting well into late-summer/early fall.
A few weeks into making some of the most significant changes such as soil amending, applying fertilizer, pruning, and adopting a consistent watering routine, you’ll start to be rewarded with bushier, healthier growth, bringing with it additional blooms.
Combining these steps may also result in much larger blooms – in some cases double the average size (3 inches across).
Happy hibiscus planting!