Gardenia: do these leaves look ok?

[JLem]

I recently bought a Gardenia ‘Fortuniana’ (Gardenia jasminoides), repotted it to get it out of the plastic pot, and have had it in a south facing window. It’s been several weeks and things seem to be ok, but I’m not sure. Some leaves are dark green, others are a yellow-green with darker green veins. Some lower, interior leaves are yellow. Is this normal or are these signs that something is wrong?

 

[Chuck]

View attachment 62437View attachment 62438View attachment 62439View attachment 62440I recently bought a Gardenia ‘Fortuniana’ (Gardenia jasminoides), repotted it to get it out of the plastic pot, and have had it in a south facing window. It’s been several weeks and things seem to be ok, but I’m not sure. Some leaves are dark green, others are a yellow-green with darker green veins. Some lower, interior leaves are yellow. Is this normal or are these signs that something is wrong?

Yellowing leaves with green veins means, probably, a lack of nitrogen. To a lesser degree it could also be a lack of iron. To be safe I would fertilize and I would also apply Iron Chelate.
You didn't say what type of soil you repotted with. Gardenias MUST have acidic soil and most commercial potting soil is basically neutral with maybe slight acidity. If the soil isn't right the plant has a hard time of uptaking nutrients.

 

[oneeye]

The horticulture term is: Iron chlorosis lock-out. Since you just repotted your plant into new soil, I wouldn't add any fertilizer to the plant, because new potting mixes always have a nutrient change in them to start with. The problem you have with your Gardenia is call nutrient lockout due to the pH swinging higher. When you add tap water to your plant over a period of time and keep the soil saturated for long periods of time, it will raise the pH and Lock out iron. Gardenia's are sensitive and only grow in pH range that is only between 5 and 6 pH. The best way to fix the problem is to change the water. Use acidic water or natural pH'd or filtered water and that will return the leaves green again. . Just a little note: Gardenias are the most beautiful plants with the most fragrant flowers, but "Gardenia's make the worst house plants", and will almost always give you problems while they are indoors. They do best outdoors.

 

[oneeye]

If you look at the pH nutrient absorption chart you see that Iron "orange color" drops with a higher pH and becomes less available. Iron is most available with a pH of 5 to 6 pH. The extra acid or hydrogen in the pH is needed to break down the iron into a liquid so the plants can use it. The Gardenia above has a pH that is higher than the pH needed to dissolve the iron. Iron Chlorosis.

 

[JLem]

Thanks for the input. I ordered some chelated iron, though some of you do not seem to think this will help if the soil is too alkaline. When I repotted I added some peat moss since I knew gardenias liked things acidic. I have some soil acidifier that I use for my blueberries - would using that work? I’m not sure how to aciidify my tap water - at least not in any controlled, measurable way.

 

[oneeye]

Use rain water or distilled water and no need to do anything else. The tap water is the problem and when you change waters, the green should come back since you added the peat to the new potting mix. .Don't allow the soil to stay wet too long and only water when the top two inches are dry.

 

[oneeye]

Just a Horticulture tip: soil acidifiers are made of 30% elemental sulfur and that is all. Also, if you have a lime base soil outdoors, "acidifiers" won't work. Save yourself some money just use sulfur cut with a little sand to lower the pH but only if your soil is lime free.