This is my bougainvillea, Betty. She may not look like much now, but if you had slept for three straight months, you’d have a severe case of bedhead too.
Before Betty the Bougainvillea can return to posting selfies on Instagram (she’s an aspiring plantfluencer), she will need a trim and some fertilizer.
I know this (now) because back in the early days, I used to have three bougainvilleas. But more on that later.
I’ve since learned that bougainvillea’s showy, colorful foliage requires quality plant food supplements in addition to plenty of sunshine and warm temperatures.
In this guide, you’ll learn:
- Why you should fertilize your Bougainvillea
- How to choose the right fertilizer for your Bougainvillea
- Timing and frequency of applying Fertilizer for your Bougainvillea
- And much more!
Here is a quick list of my Top 5 Fertilizers for Bougainvillea, starting with my favorite product at #1.
BGI Fertilizers Bougainvillea Fertilizer
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Neptune's Harvest Fish Fertilizer 2-4-1
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Fertilome (10505) Bougainvillea & Flowering Vine Food 17-7-10
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Miracle-Gro Bloom Booster Flower Food
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DR EARTH Flower Girl Bud & Bloom Booster
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My Overall Top #1 Pick: BGI Fertilizers Bougainvillea Fertilizer
BGI’s Bougainvillea Fertilizer is my #1 pick for several good reasons, the first being that it is formulated specifically for bougainvilleas.
If bougainvilleas have one fault, it is their thin root systems (check out my other article on fertilizers for root growth). This product addresses this issue directly. Its fertilizer composition is 6-8-10, meaning 6% Nitrogen, 8% Phosphorus, and 10% Potassium (sometimes called potash).
The phosphorus and potassium in this fertilizer encourage strong root growth, while the slightly lower nitrogen content supports vine growth without sacrificing blooms.
Did you know? The colorful blooms on bougainvillea are actually modified leaves (called bracts) that surround the tiny white flowers at the center. This vibrant foliage is what attracts pollinators and is responsible for bougainvillea’s popularity worldwide.
My top recommended fertilizer also contains 5% Iron to encourage and help maintain vibrant colors. It delivers quick results when sprinkled on the soil and then watered in.
Top 5 Best Fertilizers For Bougainvillea
In a hurry? No worries! Below are my top 5 fertilizers for your Bougainvillea!
- BGI Fertilizers Bougainvillea Fertilizer (My Top Pick)
- Neptune’s Harvest Fish Fertilizer 2-4-1 (Best Pick for a Quick Boost of Nutrition)
- Fertilome (10505) Bougainvillea & Flowering Vine Food 17-7-10 (Best Pick for Rapid Growth)
- Miracle-Gro Bloom Booster Flower Food (Most Versatile Pick)
- DR EARTH Flower Girl Bud & Bloom Booster (Best Organic Pick)
Why Should You Invest In A High-Quality Fertilizer For Your Bougainvillea?
Bougainvilleas are notorious for their thin, brittle roots. They also don’t particularly like being transplanted.
I learned this the hard way when I transplanted two younger bougainvilleas into my garden’s flower bed, and they not only did not thrive, they died. They suffered damage to their roots and could not get the nutrients they needed from my alkaline, clay-like native soil.
Bougainvilleas actually perform best when they are somewhat “pot-bound.” But this also means that the soil they are in needs to be replenished regularly.
Like all plants, Bougainvillea plants require phosphorus, potassium, and nitrogen to grow (more on that below).
Fertilizers supply these nutrients in the right proportions, ensuring that the plant gets the necessary nourishment.
Regular fertilization supports the root system, the vines, and abundant blooms. If you want your bougainvillea to thrive and look its best, fertilizing it is a must.
What Should You Consider When Choosing the Right Fertilizer for Bougainvilleas?
Fertilizer is comprised of three main ingredients: nitrogen, phosphorus, and potassium (N, P, and K, respectively).
Most fertilizers will have three numbers labeling these three key ingredients (they look like this: 4-12-6). These numbers represent percentages.
- Nitrogen (symbol N) is used for leaf development and vivid green color
- Phosphorous (symbol P) is used to encourage root growth
- Potassium (symbol K, sometimes called potash) is used for root development and disease resistance
Most bougainvillea-specific fertilizers will have higher phosphorus and potassium content relative to nitrogen. This is to promote leaf, stem, and root growth (which can sometimes be poor) and encourage colorful blooms.
Organic Versus Inorganic
Organic fertilizers, derived from natural materials like fish, compost, and bone meal, release nutrients slowly over time and can improve soil health. In addition, they don’t tend to leave a crusty residue behind.
However, organic fertilizers usually contain fairly low concentrations of plant nutrients, which then have to be converted into inorganic forms by decomposition, soil bacteria, and fungi before plants can use them. This process can take several seasons to complete.
The good news is that over time and with repeated applications, organic fertilizers will improve soil volume and structure and feed its beneficial microbes.
In contrast, inorganic fertilizers are usually made from synthetic materials (such as ammonium sulfate or phosphate) and are designed to release nutrients rapidly. They are delivered in a form that is immediately bio-available to plants.
However, they are highly water-soluble and are quickly lost from the soil, so you will need to fertilize your bougainvillea several times during the growing season unless you use a specially formulated, slow-release product.
Many inorganic fertilizers are super-concentrated, too, so it is easier to use too much and damage your burgeoning root system. But on the plus side, this type of fertilizer is usually easier to find and will be a bit cheaper than its organic counterpart.
In my opinion, the best approach to fertilizing your bougainvillea is using a combined approach, utilizing both organic and inorganic compounds.
The synthetic fertilizer will give results during this season, while the addition of organic material will slowly build up your soil’s volume and quality over time.
Like bougainvillea’s fellow hot-headed cousin, the cactus, it prefers high temps (+- 90 degrees F), well-draining soil, and being left to dry out between waterings.
A great soil recipe that I recommend for bougainvillea is 70% Citrus Mix (drains well), 20% perlite (keeps the soil aerated), and 10% worm castings (for organic matter).
For a bonus jump start when transplanting your bougainvillea, sprinkle a teaspoon of mycorrhizal fungi granules on the roots before putting the plant into the new pot.
My Reviews of the Best Fertilizers for Bougainvillea
1. BGI Fertilizers Bougainvillea Fertilizer (My top pick)
With an NPK ratio of 6-8-10, this fertilizer is heavier on potassium and potash to encourage blooming and strengthen root systems.
Formulated specifically bougainvillea, this sprinkle-on, granular formula is easy to use and effectively promotes the growth of leaves and bracts.
|+ Promotes vigorous growth and blooms through its mix of vitamins and minerals
+ Easy to use, simply sprinkle on top of the soil and water afterward
+ Also excellent for plumeria and hibiscus
|– Needs to be applied every bloom cycle, or every four weeks
2. Neptune’s Harvest Fish Fertilizer 2-4-1 (Best Pick for a Quick Boost of Nutrition)
This fish-derived fertilizer with 2% nitrogen, 4% phosphate, and 1% soluble potash gives your struggling (or healthy!) bougainvilleas a quick natural boost.
Organic fertilizer made from fresh North Atlantic fish is cold-processed and provides plants with natural vitamins, amino acids, enzymes, and growth hormones to thrive.
This is an excellent, easy choice that all plants love!
|+ All-natural, fish-derived ingredients
+ Low NPK ratio means it is safe even for younger plants and seedlings
+ Excellent for giving your struggling bougainvillea the burst of nutrition it needs.
+ Also feeds the beneficial microbes in the soil, which benefits
|– Slight fishy smell upon first application, but it soon dissipates
3. Fertilome (10505) Bougainvillea & Flowering Vine Food 17-7-10 (Best Pick for Rapid Growth)
This 17-7-10 Fertilizer contains 17% Nitrogen, 7% Phosphate, and 10% Soluble Potash.
The higher percentage of nitrogen boosts leaf growth as well as blooms.
Formulated specifically bougainvillea, this sprinkle-on, granular formula is easy to use and effectively promotes the growth of leaves, stems, and bracts.
|+ Higher nitrogen content than the others stimulates rapid growth
+ Granular, easy to apply
+ Excellent for other flowering vines too!
|– Higher NPK ratio can be too strong for young plants. Be cautious about applying only the directed amount for your plant size.
4. Miracle-Gro Bloom Booster Flower Food (Most Versatile Pick)
This 15-30-15 general flower fertilizer contains 15% Nitrogen, 30% Phosphorus, and 15% Soluble Potash.
The higher phosphorus content promotes more blooms and more vibrant color.
Just add one pre-measured scoop to your one-gallon watering can to feed all your flowering plants quickly and easily.
|+ The 15-30-15 NPK ratio boosts stem, leaf, and flower growth quickly
+ Easy to mix and apply
+ Trusted name of Miracle-Gro
|– Synthetic fertilizer needs to be used frequently (every 7-14 days)
5. DR EARTH Flower Girl Bud & Bloom Booster (Best Organic Pick)
This 3-9-4 organic formula contains a premium mix of alfalfa meal, fish bone meal, feather meal, and minerals.
Bonus ingredients include probiotics to feed the soil and mycorrhizae (an organic species of beneficial soil fungi that collects and stores nutrients and water).
Simply mix the granules into the soil around the base of your bougainvillea and water in afterward.
|+ 100% organic and natural formula is people and pet safe
+ Feeds for several months
+ Free from GMOs and pathogens
|– Ounce for ounce, a bit pricier than the other options
My Top Pick: BGI Fertilizers Bougainvillea Fertilizer
Although there aren’t many bougainvillea-specific fertilizers, this product falls neatly into this category. Heck, it’s even got GAIN in the name!
This product is unique in that it is formulated for the specific needs of your beautiful bougainvillea, and it also contains 5% iron to support vivid color in the bracts.
Like most granular fertilizers, this one is easy to apply and doesn’t require mixing. You only need to apply it once per month, and the higher potassium ratio addresses and supports the brittle root systems that can afflict bougainvilleas.
How To Fertilize Your Bougainvilleas
If your bougainvillea has been planted in the ground, aim to fertilize it at least twice a year with a balanced, slow-release granular fertilizer. You can give the first dose of fertilizer when your bougainvillea starts waking up from its winter dormancy, and again in July when summer is in full swing.
A good rule of thumb is to use ½ cup per four feet of vine height. Sprinkle on the area surrounding the base, and mix it into the soil with a trowel. Be sure you water it afterward so the nutrients can soak in.
If your bougainvilleas are potted plants, they will require fertilizing more often. Aim for once monthly during the spring and summer. Bougainvilleas should not be fertilized during their dormant period in the wintertime.
Pruning Your Bougainvillea
If you’ve been feeding and taking care of your bougainvillea for a while, there’s a very good chance that it has started to grow a bit wild, and now you have to prune it. This is especially true if you want to train it to grow in a specific area or shape.
New blooms and sprouts grow in all directions. If the bougainvillea is not trimmed and trained, it can grow huge and wild.
Here is a short but helpful video primer on pruning your bougainvillea.
Natural Fertilizers for Bougainvillea
If you don’t want to pick up one of these listed fertilizers just yet, you’re in luck because there are several natural options that your bougainvillea will love!
The most important things you can give your bougainvillea are plenty of direct sun and not too much water. They are happiest in hot, dry conditions. However, if you want to do even more for them, there are many natural options.
Fish emulsion (like the one mentioned in #2 above) promotes plant growth and feeds the soil. In addition, bone meal provides calcium (for growing strong stems), and compost tea is rich in nutrients. A few more options are bat guano and rabbit droppings, both of which are high in nitrogen.
If you want to go even more natural, look no further than your kitchen! Banana peels, egg shells, coffee grounds, and homemade compost are all organic, natural fertilizer options.
Final Thoughts on The Best Fertilizers For Bougainvillea
Bougainvilleas are loved worldwide for their huge size and vibrant colors. They adorn entire buildings in warmer climates all over the world, bringing their own kind of lush beauty to an otherwise arid landscape. They don’t need much water and can take all the sun and heat that mother nature can dish out.
However, there are some wonderful fertilizers available that can help your bougainvillea maximize the nutrients it receives to make it even more beautiful and healthy.