Scale insects here to stay?

Amanda219

Hi, I've cut to the ground 2 hydrangea infested at the front of my house and have yet to see what happens with those.
Scale are on a holly hedge and a star jasmine at the back. Do I remove the hedge and jasmine to start those again or find alternative plants, before scale take over the rest of the back garden, or is that a pointless task to save 1 hydrangea and a couple of rhododendron and every other woody plant (being the majority)?
They arrived here somehow once, my guess is they'll arrive again, unless I grow everything from seed and then no guarantee.
Do I need to accept this doom for infested plants that can't survive?

Borderline

Scale insects are usually a sign that the plants are under a bit of stress. Whilst there are some shrubs that are affected more than others, it's more important to assess what are the reasons. It is fair to say that in some cases, it's brought in but with the right care, they can be dealt with.

Lack or water to the roots, shrubs not growing in their preferred positions, example, type of soil, too much sun or vice versa. Close planting and over crowding of plants that have the potential to grow tall or big, or in some cases, over hanging tall shrubs/trees stunt their growth.

In most cases, shrubs will recover in time once the conditions improve, provided they are reasonably mature already. Established shrubs are unlikely to be affected health-wise. The leaves may look tatty and their growth slowed down, but not to the extent that whole shrubs needs removing due to scale insects.

Hydrangeas can be cut down in time, so new branches will grow again, but the issues may return if the conditions are not improved. If the infestation is overwhelming, it may not be worth keeping, especially in a new plant.

Amanda219

Thank you, I really didn't want to take a knee-jerk reaction.  I shall see what happens with the front of the house, hydrangea there are the youngest shrubs at 7yrs, shrubs I have greatest fear for are 25+ possibly at least 50yrs. I do what I can to aid the mature back garden, I am hoping that's why scale has not come to my attention before now. I have held off inspecting all of the back with fear of what I may find. 
All things considered, I may not have a disaster on my hands, just an irritation.