On 7/5/2009 7:05 AM, Douglas R. Hortvet, Jr. wrote:
All,

Just found this group - what a stroke of luck.

Have a nice sized gardenia in a pot - last week or so most all leaves yellowed and started
falling off.

This after a light application of sulphur and fertilizer.

When collecting the fallen leaves for disposal - observed the soil was heavily infested
with ants.

Called in to the local garden talk show and was advised to use Spinosad - had heard of
this before however never used the product.

In researching the net - find this is an ingredient, rather than a named product one can
purchase.

Recommended application method for ants is a drench - so need a water soluble form.

Has anyone used a Spinosad product on gardenias with success?

Any recommendations for a brand name product are greatly appreciated.

Thanks in advance.

Regards,

Doug

For ants nesting in a flower pot, I use a drench of malathion. You can
even mix it to 1/2 the strength recommended for aphids.

Yellowing of a gardenia can have several causes:

Feeding the plant when the soil is dry will result in burned roots when
you next water it. The leaves will yellow, curl, and die.

Gardenias need perfect drainage. If the pot has no drain hole, the
plant is drowning. Even if there is a drain hole, you could be
over-watering. Gardenias need soil that is constantly moist but not
soil that is soggy. If the soil is too wet, the plant yellows.

Gardenias need more than merely acid soil. They need some extra iron, a
lack of which can cause yellowing. For iron, buy iron sulfate. Until
the plant recovers a healthy green, however, use this sparingly (about 1
Tbs in a large pot once a month).

Gardenias also need more zinc than most plants (except for citrus).
Instead of yellowing, a lack of zinc will more likely result in flower
buds dropping without blooming. However, a severe lack zinc can cause
yellow blotches on the leaves. Zinc sulfate seems hard to find these
days, but some Ace Hardware stores carry it or can order it. Buy the
smallest package you can get; it will last for years. A large pinch of
zinc sulfate should be added to the pot monthly.

Adding sulfur (as you did) is good. However, you also need some soil
bacteria to convert the sulfur slowly into sulfuric acid. A light
topping of active compost will provide the necessary organisms.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening diary at http://www.rossde.com/garden/diary