I have two on standard. I am zone 5. I prune them almost every other month during the growing season but do not prune after September-ish so that new growth isn't destroyed by winter chills. The FIRST TIME, new growth appears in spring it is very white and splotchy with green; very beautiful. After that it takes a while for new growth to turn white and some does not. I will say that they are prone to japanese beetles and aphids on the new growth, so keep an eye out. These are easy tackled with pinching and washing lightly. Also, I have one that receives shade in the winter, but almost full sun in the summer and it has no issues coming out of dormancy in spring; it thrives! However, I have one that receives full sun, all year, and I lost it its second year and had it replaced (for free yay!) but I think it was dessicated from sun and breezes in winter. These take hard pruning very well and bounce back only a week or two afterward.

green velvet boxwood evergreen, stay small patriot hosta will need to be kept well watered to look good in your amount of sun. peach drift rose Roses have issues with Japanese beetles and may have disease problems, so if you want low care, choose something else IME little henry sweetspire will stay around 2.5’, spring flowers and red fall color golden mop cyprus will eventually get to 5’ in all directions and IMO pruning doesn’t look good with these, so unless you want to widen the space you will need to replace eventually. pee wee oak leaf hydrangea 4’ in all directions, so too wide for a 3’ bed, spring flowers and great fall color panicled hydrangea this is just the species name, and this particular species has cultivars that range from about 4’ in all directions (Bobo) to over 15’. What cultivar is the nursery recommending? You would need to plant the smallest kind and have a slightly wider bed. Some have fall color, and bloom lasts for months, starting in summer. This area has sun from early morning until midday, and then bright light after that since it is only shaded by the house, so plants that will be happiest will be sun to part sun plants to, not shade plants. You really want to make your bed at least 2 feet deeper front to back as both GG48 and I have recommended It will be easier to choose plants and maintain the garden and will look far better than the current 3’ strip which only has room for a few shrub selections due to the narrowness. The shrubs won’t need frequent pruning and they won’t be growing against the porch and over the lawn, and the garden will look better balanced against the size of the house.

I googled it and it seems they root pretty easily. Taken from Midwest Gardening site: " Dappled willow can be propagated from softwood or semi-hardwood cuttings. To produce new plants, just plant 8” cuttings of stem without leaves into consistently moist soil in a small pot or nursery bed, they will generally root easily. " I do a lot of cuttings. I use pro mix and perlite mostly. Since cuttings have no roots, you want the medium to be moist but not wet. It doesn't have to be promix used, either. You just don't want anything with fertilizer.

A lot depends on what you mean by 'invasive'. All willows (Salix spp.) have aggressive roots, tree forms much more so than the shrub forms. Tree willows can grow to a very large size (60'+) and tend to have very aggressive, water seeking roots. They will invade any nearby water source (inground plumbing, water pipes/mains, irrigation systems, septic fields, etc. They are NOT recommended for a typical suburban garden. In general, shrub willows do not have aggressive root systems and will not invade or aggressively seek out water sources. However, if they have been grafted and sold as a tree form, the grafted rootstock may very well have a more aggressively spreading root system than just the straight shrub. Keep in mind that the grafted form of dappled willow is intended for use in the average garden so unlikely to have the same overly aggressive, invasive behavior as would a weeping willow, for example. How close will the hedge be in relation to the French drain?