Haven’t you felt that hollowness of the empty garden? That first year of spaced-out vines or any plant can feel lonely because there is no cover on the ground beneath them. Some neighbor might even tell you to plant some things to fill it in.
Don’t fall into that trap. With vines, spacing is as much about respecting how they will grow later than it is about filling their spots now. Crowd them and by year two it’s a battle with both mildew and pruning woes.
Why Vines Need Space
Aisle width v. The chart above distinguishes between the two. That’s an easy divide but a crucial one. Think of the vine wall as a two-dimensional space: How much leaf area does each plant claim on the trellis? (That’s determined by horizontal distance.) And what about vertical distance, can you get to the flower(s) or fruit?
Aisle width may seem trivial when the plants are small, but think kiwi or wisteria once they grows up! How about the contrast between woody perennials and annuals? Short-term plants like bush beans don’t mind being crowded, they’ll be gone by August anyhow. Cucumbers? No problem. You can get away with inches of space because you know these aren’t coming back.
On the other hand, long-term residents like woody vines (such as clematis, passion flowers, or grapes) need room to spread out. If they don’t have room, they won’t grow well because inner branches dies from lack of light and outer ones tangle up.
One variable is the support structure. A flimsy wire might hold a clematis, but it will not survive weight of a mature grape vine or a heavy wisteria. Setting heavy posts before planting, as the guide emphasizes, makes sense for several reasons including money. Digging around an established root system cost more than driving a post into bare ground.
Kiwi? You’ll want a large T-bar system, with lots of aisle space. For airflow and for accessing fruit at harvest time, 15 feet between rows is essential.
Training is where most home gardeners lose the plot, but you can’t fix bad spacing with good training. Poor training doesn’t help correct for poor spacing. Train those vines to weave together into one continuous canopy if they’re eight feet apart, but you won’t get there if they’re only four feet apart. Leaves will then stack up, not layer out, and create a less-than-clean appearance.
To avoid fungal problems, leaves should of receive sunlight from several angles. Higher humidity inside the grapevine foliage wall makes things worse. Powdery mildew likes airlessness.
The timeline from planting to a fully canopied vine is deceptive. Year one is mostly root development. Year two is mainly leader training (main trunk). In year three, the canopy start to fill out. And patience is the most difficult thing.
You think they aren’t green enough, so you add more. That’s not good. All that empty space in year one is good. This means you’re allowing them to develop strong roots and letting air circulate around the plants.
Spacing of the vines: Forecasting. Don’t plant for now; plant for 10 years from now when the plant will be more than what’s in your hand today, but only a frame. Leave plenty of aisle room between fruit vines. Tame the mesh so annuals don’t get lost in them.
A wisteria is no little climber; it will overwhelm your fence if you permit. What you want is not just full but also manageable; and productive. Don’t try to fill every inch of dirt; start with the stakes, measure twice, and then hold back again. Air and light need to flow through the empty spots, too.
Actually, a wisteria is more luxurius than most. It can dissapears into the background if you don’t manage it properly. Just be careful based off how fast they grow.