When watering new shrubs that are built for dry conditions, you soak them deeply and far apart, not a little every day. Give them a deep soak about once a week through the first season, let the top inch of soil dry out between drinks, then taper off over the next year or two. That spacing is what makes a drought tolerant plant actually drought tolerant.
My neighbor leaned over the fence the day I planted a Ceanothus 'Victoria' on the dry slope by my gravel driveway. "That'll be dead in a month if you don't water it every single day," he said. I gave it one slow soak a week instead. By late summer it had pushed roots down into the slope and held its leaves through a hot dry stretch that browned half his border. His daily-water plan would have rotted mine.
Here is why spacing beats frequency for your plant. Roots chase water, so they grow toward wherever the moisture sits. Water a little every day and the moisture never sinks past the top few inches, so your roots stay shallow and lazy near the surface. Deep watering shrubs the right way pulls water down deep into the soil, and the roots follow it down. Those deep roots are the whole point. They reach moisture that surface heat can't touch, which is what carries your shrub through a dry spell on its own.
Your shrub with shallow roots looks fine until the first real heat wave, then it wilts fast because nothing is left to draw on below. That is the trap of daily sprinkling. You feel like a careful gardener while you quietly train the plant to lean on you forever.
When you start establishing drought tolerant shrubs, the clock is longer than you expect. Clemson notes that establishment takes one to several years. Bigger plants take longer because they have more root to rebuild. A one-gallon plant might settle in within a season. A large balled shrub can need two or three years before it stands on its own. Even a fully grown shrub still wants a deep soak in an extreme drought. So your watering never truly drops to zero.
Soak the root ball and the surrounding soil slowly until water stops sinking in. This settles the soil and removes air pockets around the roots.
Give one deep soak about weekly, more often in heat, and let the top inch of soil dry between waterings so roots reach downward.
Stretch the gap to every two or three weeks. The plant is finding its own water now, so you are weaning it off the hose.
Stop routine watering, but give a deep soak during any extreme drought, even years later, to protect the plant through the worst of it.
Make every watering count by going slow. A quick blast runs off the surface and down the slope before it soaks in, which fooled me more than once on that gravel-edged bank. Set your hose to a trickle at the base, or use a soaker line. Let it run fifteen to twenty minutes so the water sinks deep instead of spreading wide.
Then lay down mulch over the root zone. A 2 to 3 inch (5 to 8 cm) layer of wood chips or bark keeps your soil cool, slows evaporation, and stretches the days between waterings. Keep it pulled back a couple inches from the stem so the bark stays dry. This is the heart of watering new shrubs the smart way. Mulch plus deep, spaced soaks beats a daily splash every time.
Read the full article: Drought Tolerant Shrubs: 15 Water-Wise Picks
