Any chance of a pic or two? Although not usually white, ants farm aphids for their honeydew.

tj

If you have sticky white it is most like there is another pest. Check for scales, aphids, etc. These pests secret a honey like substance that attracts the ants. The ants then carry the eggs of the pests and deposit it elsewhere. Destroying the ant colony will stop the spread but check for the presence of scales first. They are tiny oval shaped blobs that lay flat on the leaves and stems and do not move. Aphids can be various colors but they have legs and can move around. If you are seeing distinct white blobs in leaf axil or branch joints they are mealy bugs ( a kind of scale insect). If the white blobs are on leaves then they are likely woolly aphids. Gardenia tends to have mealy bugs. Treat the mealies with spray of alcohol diluted 50-50 with water or with insecticidal soap.

Thanks for the replies to far.

Follow up to the OP: Here are two different locations on my plant where the white goo can be seen.

Those are mealy bugs. Take q-tip and dip it in rubbing alcohol and clean them out of there. Make sure you get the alcohol into nooks to get as much of it out and kill any eggs too. Look carefully elsewhere too. After that hose it down. Gardenia is a magnet for these bugs.