One of my favorite late fall/winter blooming plants is the sunny "Mexican Marigold" (Tagetes lemmonii), which provides cheerful color in the colder months.  This marigold isn't your small garden bed variety.  It is a large, sprawling shrub that is assertive in both color and fragrance. 

The Mexican Marigold is an evergreen shrub 4'x6' with 2” bright yellow daisy- or marigold-like flowers.  It is native to southern Arizona and northern Mexico.  The shrub provides its best display in the short days of fall and winter and may extend its display into spring in overcast weather.  It will continue to bloom, but to a lesser extent, in other seasons.   

The shrub's finely cut leaves are extremely fragrant when touched.  The pungent aroma is described as a combination of marigold, mint, and lemon.  Some people find the smell unpleasant.  In addition, some people are sensitive to the oils in the foliage and should wear protective clothing when pruning.

The Mexican Marigold grows well in sun and part shade.  Too little sun will result in a leggier plant.  The shrub prefers well-drained soil, although it tolerates clay and poor soils.  After being established, the plant is very drought tolerant, but it will look better with a little irrigation.  The shrub can be pruned any time for size or shape, although pruning may reduce or delay flowering.  It is frost tender, but rebounds quickly and is hardy to at least 20-25° F and perhaps even 18° F.  The plant is exceptionally deer resistant, probably due to its strong fragrance.

I can personally attest to the hardiness of the Mexican Marigold, at least in a nearby coastal climate.  My parents planted several shrubs on the edge of their yard in clay soil, without irrigation, in an area roamed by deer.  The plants survived for years despite their neglect, consistently providing bright color at a muted time of year.