Probably the only certain guard against deer browsing is using a fence that they cannot jump over. There are many to choose from. I recommend a small garden just off the house with a lovely ornamental fence and gate for my customers who cannot live without their favorite deerlicious plants; roses and hydrangeas being at the top of the list.
And then what to do when a fence just won’t do? Though there is never a 100% guarantee against deer browsing, I have been planting resistant gardens for years. In general, fuzzy, pubescent leaves will make a deer gag. These plants include Dusty Miller, Artemisia, Lavender, Catmint, Russian Sage, and Lamb’s Ears and Blue Mist Shrub (Caryopteris clandonensis).
Deer will not eat ferns nor most ornamental grasses. Daffodils, Alliums, and Winter Aconite are good hardy bulb choices. The most successful flowering annuals have been Annual Vinca (Catharanthus rosea), Ageratum and Cleome. I have been growing a long list of deer resistant perennials. Among them are: Ginger, Helleborus and Bleeding Hearts for shade. Baptisia, Coreopsis, Rudbeckia, Catmint, Peonies, Anemones and Goldenrod all have proven resistant in sun gardens.
Two of the best evergreen shrubs in the war against deer are Boxwood and Cherry Laurel. All Barberry shrubs are deer resistant. I grow the low varieties with purple foliage like Berberis thunbergii var. atropurpurea ‘Royal Burgundy’. Barberries produce berries that attract birds as do Winterberry (Ilex verticillata), Beautyberry (Callicarpa americana ) and Bayberry (Myrica pennsylvanica); three native shrubs worth adding to your deer resistant garden.
Each garden has its own degree of deer resistance which can change due to increased deer population, availability of natural foraging areas and other conditions. I knew a landscaper who planted a very populated area with the most toxic of plants; Aconitum and Digitalis. The deer completely leveled the garden. Now that WAS some hungry deer!
In retrospect I always advise monitoring your garden plantings. Apply netting or deer repellent if you must. Protect your investment.