Desolation

You plant an obsidian acorn in solid ground and spend an hour chanting a litany of curses to the natural world, after which the land within 1 mile of the acorn becomes infertile, regardless of its previous state. Nothing will grow there, and all plant life in the area dies over the course of a day. Plant creatures are not affected. Spells that summon plants, such as entangle, require an ability check using the caster’s spellcasting ability against your spell save DC. On a successful check, the spell functions normally; if the check fails, the spell is countered by desolation.
After one year, the land slowly reverts to its normal fertility, unable to stave off the march of nature.
A living creature that finishes a short rest within the area of a desolation spell halves the result of any Hit Dice it expends. Desolation counters the effects of a bloom spell.

Ritual Focus. If you expend your ritual focus, the duration becomes permanent. To expend a ritual focus, pay twice the cost of the material component in the ritual. This might represent the material component’s construction of higher-quality materials, or it might simply mean using more of the listed material component, whichever is most appropriate.