Understanding Soil P & K

The arrival of March tells us the first day of spring is just weeks away. As we all know, March Wisconsin weather will bounce between spring and winter, as evidenced this past week. Although early, with favorable weather, the gardening calendar offers a few choices this month.

The safest bet for outdoor activities throughout Wisconsin for this month is pruning. March is prime time to prune apples. The goal when pruning fruit trees, unlike shade trees, is not aesthetics but function. Sound pruning techniques improve fruit production. Apple trees need a good strong framework, plenty of horizontally orientated branches, and some openings in the canopy to allow light and air to penetrate. Remove suckers originating from the base of the trunk, along with watersprouts, the fast-growing vertical branches that tend to clog up tree canopies.

For all deciduous trees, pruning now allows you to see the framework and make good pruning decisions. Try to maintain the natural form and growth habit of each individual tree. Start by removing any broken or dead branches, remembering to always cut back to a side branch, lateral shoot, or bud. Eliminate crossing or competing branches as much as possible. Most trees can be pruned now but avoid bleeders like maples. Remember to complete pruning any oaks by the end of March to alleviate oak wilt concerns.

Deciduous shrubs can be pruned this month but proceed with caution on those that flower. Remember the rule — shrubs blooming in spring before about June 15 formed their flower buds last season, so any dormant pruning will be removing those buds. Ideally wait and prune spring-flowering shrubs, including forsythia and lilacs, until right after they have finished blooming.

As we advance through March, assuming snow cover is gone and weather conditions are mild, gardeners, especially in southern Wisconsin may be tempted to get out and start working in garden soils or on lawns. Do not do any soil tillage until soils totally thaw out and dry out. If in doubt, wait, as the consequence of working soils too early is problematic soil clods all season long. Limit March lawn work, as conditions allow, to cleaning up debris from winter and last fall. Hold off on everything else.

Want to make the most of a warm day in March? Go out and survey the yard, noting damaged plants and problem areas to address later this spring. Enjoy early blooming spring-flowering bulbs starting their annual show. Make plans for upcoming yard and garden maintenance and projects to address in the coming months. It rarely pays to rush the season.