I think we're picturing a very different level of brightness achievable per plant. Replacing one street light would require a very large amount of glowing vegetation. Just the maintenance would be prohibitive. A city would need more gardeners than all other civil servants combined. And nevermind whether the fertilizer is produced from sewage or petrochemicals the runoff would be an enormous pollutant in its own right. Also it would be least effective in winter when the need for artificial light is greatest.