Exactly what your plants are telling you, is all about how their language is interpreted...
“My plants are all dead, what do I do?” That question has been processed and reprocessed now for nearly a month. Not everyone has asked that question. There are a great many ‘seasoned’ master gardeners; this is not their first rodeo either. Still, it is disheartening, despite whatever level of expertise you possess.
Looks can be deceiving. First of all, yes, the leaves are dead, the plants are likely not. With regard to broadleaf evergreens: laurel, aucuba, holly, osmanthus, eleagnus, photinia, euonymus, southern magnolia, as well as semi-broadleaf plants such as nandina, a whole range of differing foliar reactions have occurred. Learning to differentiate between these similarly classified plants’ reactions (and ours for that matter) goes a long way in helping each of us to grow horticulturally.
Nandina are correctly considered semi-broadleaf. That means in mild winters theyretain most of their foliage; they lost every single leaf this winter. On the other end of the spectrum, laurels and aucuba leaves are quite dead, but hang on fiercely. Others, like many hollies, euonymus, and osmanthus have also defoliated; some completely, others mostly, while a few, hardly at all. Magnolia grandiflora, a.k.a. Southern Magnolia has shown significant ‘bronzing’ but otherwise few effects. However, other cultivars of Magnolia grandiflora, seem to have a bit less resilience to cold, and therefore show more desiccated foliage.
Damage is not limited to broadleaf evergreens. There are a few types of conifers that have suffered as well. These are the plants, where I have the most questions and concerns. Leyland Cypress, and many other types of ‘Cupressus’, are Mediterranean in origin. Likely, most have experienced foliar ‘burn’, some perhaps worse.
I can’t foretell the weather future (or any future for that matter). It is the third week in January. There are two more months of winter ahead. Keep listening. Stay patient.