The taller evergreens in the photo are Dwarf Alberta Spruce (botanical name Picea glauca 'Conica'), and their smaller companions appear to be a type of juniper (there are dozens of varieties). The juniper appears to be one of the very commonly-grown non-dwarf types (which would normally mature around 4 or 6 feet high and more than that in width), so they would be over-pruned if restrained to this size for the long term. Junipers, like many needled evergreens, do not prune well in the sense that they cannot regrow from older wood that pruning eventually cuts into as the plant ages. This creates a poorer plant appearance and stunted vigor if they are not allowed to become larger with age. Shearing them, which cuts across needle clusters, also can leave brown tips that will not recover, though sometimes new growth emerging afterwards can help to cover that ragged appearance up since it's more minor browning than other causes.

There are several species of spruce grown in our region, but as a group, despite their popularity in landscaping, they are best suited to cooler climates than Maryland provides. Very few native spruce occur in our westernmost counties, up in the mountains, but none occur wild elsewhere in the state. Piedmont Maryland has soils are often too heavy to their liking, and summer heat (both during the day as well as overnight) adds to their stress, predisposing the plants to other issues. Two common ailments are fungal infections that cause needle drop, and they can also be afflicted by outbreaks of spruce spider mites, which also damage needles and can cause bare patches. Spruce located in areas near sources of reflected heat or interrupted airflow, like by a building, wall, or near pavement, are the most vulnerable, especially if those areas also have compacted soil like the soil near building foundations can be.

Junipers can be infected by a different set of fungal twig blights, and while that does not appear to be the case here yet, plants pruned heavily could be more susceptible to infection because they are too dense in that outer layer of foliage. (Reduced airflow keeps leaves wetter longer after rain, making it easier for fungal spores to cause infections.) Any branches that turn brown (die) out to their tips need to be pruned off since they will not regrow.

The only recourse for leafless branches on spruce is to also prune them off; if they do not have live growth at the end, they will not recover. The bare interior of spruce, juniper, and other evergreens is normal as they age, though it can be exacerbated by plants growing in too much shade since they prefer full sun (6-8 hours or more of direct light), as well as by pruning that creates a dense outer layer of foliage instead of the more open natural shape of the plant. If a group of branches needs removing and they leave a hole in the plant's canopy, that will not fill back in again since that older inner wood cannot produce new leaves. Drought stress, even though spruce and juniper have moderate drought tolerance, can also result in needle browning, so sometimes it's hard to pinpoint the exact cause of this symptom.

If mites are the culprit, they can be suppressed with applications of horticultural oil, being careful not to apply it during weather that's too warm. Repeat applications will likely be necessary, at least during spring and fall when the mites are actively feeding and reproducing. (Note that their feeding damage might not show up until summer, but that's not when treatments will have any impact.) Needles damaged by feeding will not turn greener even if the mites are successfully treated, so a plant will need to wait for new growth to look better.

Miri