A Complete Guide to Gardenias
A Complete Guide to Gardenias

A Complete Guide to Gardenias

With stunning white blooms and shiny evergreen leaves, Gardenias are a great way to add fragrance and beauty to your home and garden. These pretty shrubs are known for being finicky, but they can actually be easy to grow as long as you get to know them just a little bit!

Gardenia Planting

Choosing the Right Spot

(Set yourself up for success!)

Growing Zone

Gardenias grow in zones 7 and up. Yes, this even means the Frost Proof Gardenia! Planting zone 7, especially 7a will want to mulch really well in winter and even cover your plant when temps drop very quickly or extremely low. Gardenias are native to tropical and subtropical regions. While they can tolerate some freezing temperatures they thrive in a mild climate and are mainly grown in the warm and humid southern states. But don't worry colder areas - you can still grow these head-turners so read on...

Timing

Yes, planting in spring and fall when temps are mild is generally going to be your best bet, but this “rule” isn’t as hard and fast as many think. Hot climates that don’t general experience freezing temps can safely plant in winter and have established Gardenias in time for spring. Gardenias are warm weather plants so cooler climates do not want to plant during winter. Ideally you should plant early enough to have your Gardenias well established in time for cold temps. So zone 7, I would plant no later than mid fall and really (I'm looking at you, 7a) spring or summer will be best for planting in this zone. As far as summer, if you you keep your plants watered well and in tropical climates plant in a partly shaded location you can really plant throughout the summer as well. Plant in the evening and preferably when rain is coming for best results when summer planting.

Soil

Gardenias love acidic soil, ideally between a pH of 5 and 6. If you aren’t sure of your soil pH, you can test your soil with a soil test. Alternatively, if you have happy azaleas, rhododendrons, and blueberries you can be pretty sure that Gardenias will thrive in your soil too. But soil pH is crucial with Gardenias so don’t just hope for the best. A high (alkaline) pH will prevent your Gardenias from absorbing the necessary nutrients to grow.  If you determine you have alkaline soil, be sure to amend your soil. To acidify your soil, amend with compost, elemental sulfur, or use fertilizers specific for acid loving plants. Mulching with pine straw or pine bark will help over time as they begin to break down, but are not an immediate solution. Be sure you soil drains well. Saturated soil will promote disease and can even lead to root rot and death of the plant. To improve drainage in something like a heavy clay soil, add compost and be sure to loosen up the soil well before planting.

Sunlight

Generally you will see full sun recommended for Gardenias. However part sun is best in warmer zones, especially tropical zones 9 and 10. A spot with morning sun and afternoon shade is ideal especially during the summer. Although you can reduce the potential harmful effects of full sun in hot climates by keeping up on your watering. Keep the soil moist but not wet. A good rule to follow is water when the ground begins to dry down at least an inch or two. Mulching will help keep your soil moist longer and reduce your watering needs.

Planting your Gardenia


Planting Illustration

Step 1:

Dig a hole twice the width of the root ball. Position your plant in the hole. Make sure the top of the root ball is slightly higher than the original grade of the bed. Also check to make sure it is straight from all sides.

Step 2:

Fill up hole with water before placing new plant in hole in order to saturate the surrounding soil.  Once the water is absorbed place your plant in the hole and water thoroughly.

Step 4:

Mix the potting soil and the soil removed from the hole. Start by back filling soil around the root ball. Carefully pack in the soil to remove any air pockets. Water plant thoroughly again until the soil will not hold any more water. This will ensure that your new plant will be a success.

Step 5:

Fertilize around your plant with the amount recommended on the package. 

Step 6:

Finish up by mulching around your new plant.  Apply about 2 inches of mulch around the plant and plant bed. Mulch will help keep the soil moist and weeds out.

Step 7:

Keep watered deeply with a hose every 2-3 days for 2 weeks. This is critical for plant survival. In the third week, begin to water as needed depending on the weather. Always check by placing your finger under the mulch to see if the soil is moist.

Gardenia Care

The Gardenia requires full to part sun and prefers moist, well-drained, fertile, acidic soil. Keep the soil moist, but not saturated, especially in summer and in the first year after planting. After the first year, it is best to allow the soil to begin to dry out in between watering. In very dry and hot environments, misting your gardenia's leaves daily or every other day will keep your plant happy. Mulching at about 2 inches deep is highly recommended for gardenias. Mulching will cut back on watering needs and protect your plant in extreme temperatures. Fertilize once in spring with balanced, slow release fertilizer when growing in the ground.

You don’t need to prune gardenias, but pruning after they are done blooming can help encourage a bushier growth and renew an older plant. Remove dead or crowded branches any time. Avoid heavy pruning or pruning for shape anytime from fall until bloom as buds form in fall. You definitely don’t want to miss out on those amazing, scented flowers!

The best way to prevent disease and pests is by keeping your Gardenia as healthy as possible. Proper location choice, watering, and fertilization will keep your plant happy.

Potential Problems for Gardenias:

Insects: You can treat scale, whiteflies, and aphids naturally with neem oil or insecticidal soap. For severe infections you can use pesticides like carbaryl, also known as Sevin.

Disease: Fungal infection can be prevented by making sure the planting site has good drainage and air circulation.

Bud Drop: There are a few potential causes for bud drop, but they all have one thing in common - stress to your plant. The most common causes are a dry environment, over watering, lack of light, and extreme temperature changes. Offer your Gardenia some humidity especially when growing indoors in winter.  Use a humidifier, mist the leaves daily, or add a tray of pebbles filled with water under your plant. Just be sure the water does not touch the soil and therefore cause wet feet. Gardenias like moist, but not wet soil. Be sure to let the soil begin to dry out between watering and make sure, especially when you grow in a container, that the pot does not hold water and drains out of the holes in the bottom.  

Growing Gardenias in Containers:

August Beauty Gardenia in Planter

Whether you grow your Gardenias indoors year-round or you just move your gardenias in for winter growing Gardenias in pots is a great way to enjoy this intoxicating beauty in less than ideal climates.

Gardenias have an ideal temperature range that seems to me quite conducive to living indoors with humans, 65 to 70 during the day and 60 to 65 at nighttime.

Probably the biggest challenge to growing indoors is something we have addressed before - that humidity level. Generally most homes are close to providing enough humidity for gardenias...except during the winter when our heat is running and dries out the air. So, just plan on changing things up in winter and misting, adding a humidifier, or that wet pebble tray if you want a really happy Gardenia.

Fertilizing container grown plants is different than feeding plants that are in the ground. They need more food because it leeches out when you water. If you have a good quality, rich potting soil, you will do well using a balanced, slow release fertilizer a couple times a year. I would recommend fertilizing in late winter/early spring and again in late summer. There are a lot of options though. You can find fertilizers that are specific for gardenias and/or acid loving plants, granulars, liquids, once a week, once a month, etc, etc. So go with what you know or like and follow the directions on the package. If it doesn’t have unique instructions for potted plants, you may want to check out the website to see if you can find more information or just fertilize about twice as often as recommended for plants that are in the ground.

Gardenia Varieties

August Beauty Gardenia

 August Beauty Gardenia

You truly won’t find a more beautiful hedge that one created with August Beauty Gardenias. Shiny, perfect-looking leaves catch your eye while large, lush, white blooms catch your eyes and nose. These gardenias are also lovely for mass plantings. Their blooms last up to 3 months! The mature size of August Beauty Gardenias is up to 4 feet tall and 4 to 5 feet wide.

Frost Proof Gardenia

Frost Proof Gardenia

Worried about freezing temps damaging buds and reducing flowers? Then the Frost Proof Gardenia is perfect for you. This hardy variety is also insect resistant and deer tolerant. Beautiful as a hedge, a mass planting or a focal point, the Frost Proof Gardenia is versatile in the landscape. Its mature size is 4 feet tall and 3 feet wide.

Jubilation™ Gardenia

Jubilation Gardenia

The compact Jubilation™ Gardenia is perfect for containers, or small hedges. The mature size of this evergreen shrub is a mere 2-3 feet by 2-3 feet. The flowers bloom all summer. The Jubilation™ is low maintenance and will beautify any yard from the smallest to the largest.

Kleim's Hardy Gardenia

Kleim's Hardy Gardenia

The dwarf Kleim's Hardy Gardenia is great for slopes, borders, and containers. This tough Gardenia is low maintenance and disease resistant. Expect a petite shrub of 2 to 3 feet tall and wide at maturity.

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