Need help with Gardenia


Can i have an expert advice how to take care a tree gardenia? I recently purchased a tree gardenia but It is extremely tricky to take care of it. I would really be glad if you can simplify some of my question.

Q1. How do i fertilize my gardenia? There are tons of different type of fertilizer in the store, i am at lost. There were no-one at the store could actually help me also. What type or brand of fertilizer I will require for this plant?

Q2. How do I make soil acidic?

Q3. So far I understand fertilizing a soil is different job than making it acidic. is that true?

If you can please help me on these concern I would be really glad, because I am really concern to do any foolish steps since this is a very tricky plant, lot of people told me. Can you please summarize what we are dealing here?

Thank you.



Hello, thank you for reaching out to the Toronto Master Gardeners for help with your new Gardenia.

Gardenia (Rubiaceae) are low-growing evergreen shrubs that are native to many parts of Africa and Southern Asia; it is widely grown in the Southern United States but in our northerly climate it is grown as an indoor plant.   Although these plants can grow to a height of 6 feet in a southerly climate, the only indoor species (Gardenia jasminoides) grows to a height of only 18 inches, so I am guessing your tree Gardenia is a standard (or a plant specially grown on a long bare stem – lollypop style!)

Gardenias are known for their glossy green leaves as well as their delicate fragrant blooms, but yes, they are very fussy.  I hope that the following information will be helpful in caring for your “high maintenance southern belle”

Soil – Your plant needs acidic soil; I assume that your Gardenia has come already planted in a container. You can assume that the nursery has already provided the correct planting material,  so you will not have to re-pot it for a year or two.   You know that its time to re-pot when roots appear at the soil surface or out from the drainage hole at the bottom of the pot.  Look for Azalea and Rhododendron soil as these plants enjoy the same acidic conditions.

Fertilizer – this is especially important for your plant. You should feed every two weeks from March to September and again, look for fertilizer designed for Azaleas & Rhododendrons.

Light – Gardenias do best in bright but not direct light.  If you do take them outdoors, make sure they are in filtered light.

Watering – Water carefully and thoroughly, allow the top of the soil to dry out before watering, but do not let your plant dry out completely, especially if you put it outside in the summer.

Winterize. You will have to bring your plant indoors for the winter. During  this time cut down on watering, again without letting your plant dry out completely, and eliminate the fertilizer.  You will have to provide humidity, either with a humidifier, regularly misting your plant, or having it stand on a tray of wet pebbles.

Temperature – an important key to successfully growing Gardenias is to maintain a steady temperature between 17 – 24c, When flower buds are forming you must lower temperature to mimic “spring time” temperatures of 17 or 18c. Note however that any sudden temperature swings will cause the buds to drop off.

I have included a link to the Toronto Master Gardener’s guide to growing houseplants, I hope this can be of some help to you.

I wish you all the luck with your beautiful Gardenia.