Is it safe to plant under a tree?

Yes, depending on tree roots and leaf litter. There are a few trees that emit chemicals that inhibit other plat's growth. Walnut, Eucalyptus being the most common. Then there's the shade issue.

Re shade, very few herbaceous perennials, at least, will last in miserable shade.

Here, however, with strong seasonality, you can have ephemeral perennials bloom in spring, but only under deciduous trees. In the natural state, these plants go through their life cycle quickly, before the woodland leafs over. Some make great garden plants (e.g. Virginia bluebells (below)).

There are many plants that will work but not the common ones at the big box.

Epimedium grow great under my maples, also native wood poppy native gingers.

Novicelandscaper, are you wanting to plant shrubs, ground covers, lawn replacements or …? There are numerous species that can do well for you. Let us know more about what kind of tree, how dense the shade and what kind of plants you want to grow.

It's not so much whether or not someone else thinks it's ok or not, what you decide is what's important. Any underplanting, even if it's in the form of lawn grasses, will be in direct competition with your tree for resources (water and nutrients). From the tree's perspective, it would be much better if you were to forgo the underplantings (including lawn grasses) and instead used several inches of arborist's wood chips. This eliminates the competition of under-plantings and ensures the tree gets the lion's share of nutrients and water as the mulch breaks down, with the remainder of the available nutrients contributing to increased populations of soil biota and a healthier soil.

So, now you see both sides of the coin and have information enough to make a decision that best meshes with your wants and wishes. Choices are good.

Al

Novicelandscaper said: Is it safe to plant under a tree?

Plant what?

There will be concerns...
Like... sever roots, a particularly sensitive tree may die...
Maples must have those lateral roots at the surface of the soil... cut through those and the tree falls over in a wind...

Dogwoods are easily killed by severing roots.

Way too much is made of the walnuts and hickories...
While it is true that a few plants may not grow near them, there are long lists (easily searched) of plants that won't be bothered by juglone.... If anyone wants to be concerned about allelopathy, they need look no further than their turf. Very difficult to garden in grass.

There are so many plants suited to the shade garden... Many people in the deep south focus their efforts there and avoid cutting down trees... and create gorgeous gardens under the trees.