My cape honeysuckle plants are yellowing and losing leaves.

October is the wrong time to plant any honeysuckle (in the northern hemisphere). Because of this, leaf drop is likely to be a reaction to your planting at this time. You don't say, for example, whether your plant is deciduous.........

HOWEVER. Yellowing leaves suggest a nutrient deficiency. One possibility is the PH of your soil which could effectively block vital soil nutrients from entering your plant and cause the yellowing. In addition, your plant may be in an area of your plot where the soil is too alkaline for that individual plant. Check your PH in several locations.

Does it match the soil in which you bought it? A simple technique and one which is never advocated in any gardening media - be it on tv or the written word.

Water problems? Most unlikely according to your symptoms.

Website says tolerant of heat and drought, however, newly planted shrubs in your part of the world should be kept watered for the first year while they grow roots to the natural water level. Treat it as if it was in a pot until it is established. Also feed occasionally. Once its got going it should be fine.