This is a typical look for an aging azalea, especially one that is planted very close to the foundation, where the soil is probably stressing the plant a bit (compacted, possibly rain-shielded somewhat, and maybe becoming more alkaline over time). If deer visit the yard, they readily eat azaleas, and may be responsible for some missing foliage and/or flowers, unless the plant was pruned last year, which also can remove flowers for the following spring.

Rejuvenation/renewal pruning may help, but only for a time, since this is a variety that clearly matures about this size, so eventually will get a height you don't want again, unless you prune it drastically every few years. There are shorter-maturing azalea varieties if you opt to replace it instead, or you can use another flowering shrub species. To prune, you'd cut back all branches (or at least all of the oldest branches) to within a few inches of the ground (maybe about 8" high...there's no set amount). The plant will regrow, but given the naturally slow growth rate of azaleas, it will take a few years to look full again, and it also might not flower for the year or two following the pruning. A compromise may be to do this with fewer branches at once, keeping some of the older wood so it flowers each year while you let the pruned areas recover, so with about a third of the old wood removed any given year, that makes the process take about three years to refresh the plant.

This process has been used on mature azaleas with success, including at the Brighton Dam Azalea Garden next to the Howard County - Montgomery County line, where they maintain acres of azalea plantings in the woodland understory. Every few years, a section of old plants is pruned heavily to get them to regrow more densely and bloom more abundantly. (There is a fence to keep deer out of that garden.)

Miri

Hello Rebecca,

I apologize for the significant lateness of this reply. The Ask Extension platform experienced technical problems that prevented us from receiving your response until today.

Although this answer comes too late for your question, we'll answer it anyway in case it's useful going forward: rejuvenation pruning for azaleas is best done just after flowering in spring. Pruning should not be done in late summer or autumn, as that might impact winter hardiness. You can prune before bloom next spring if you want, but be aware that doing so will eliminate all of next year's flowers, and the shrub will probably not bloom much (if at all), for at least a year following the renewal pruning, regardless of exactly when it was done.

Fertilization should not be needed, but might not hurt if applied when it's regrowing. Follow dosage recommendations on whatever fertilizer formulation you choose to use; one of the primary nutrients it will use the most of is nitrogen [N], so the ratio of the N-P-K chosen (while it doesn't need to be precise) can favor N to support leaf regrowth.

Miri