Garden Calendar for April
Stop pruning Oaks. April, May and June are considered high risk months for Oak Wilt infections. At this time the fungal pathogen is producing spores that can be carried by beetles from the Nitidulidae family. These beetles are sap feeders and will be attracted to fresh pruning cuts on oak trees.
Photo 1: Do not prune oak trees during April-June to avoid oak wilt infection. David Zlesak
There is still time to start seeds of fast growing warm season flower and vegetable species indoors for outdoor transplanting after danger of frost. These plants include: cosmos, marigolds, tomatoes, and zinnias. Cold hardy annuals can be direct seeded in the garden during April and include: calendula, sweet peas, peas, and larkspur. Cold hardy annual transplants we have started ourselves or purchased from the garden center can also be planted and include vegetables like cole crops (broccoli, cabbage, cauliflower, etc.) and flowers like pansies, snapdragons, and stocks.
Enjoy the great selection of dormant geophytes (“bulbs”) and nursery stock at local garden centers. It is important to try to purchase such material early and handle it properly. For hardy geophytes (e.g. lilies, liatris, etc.), hardy herbaceous perennial divisions (e.g. daylilies, hostas, peonies, etc.), and hardy nursery stock (e.g. blueberries, raspberries, roses, etc.) obtain and plant the dormant plants as early as possible. Planting them while they are still dormant and the ground is first workable will help them acclimate and come out of dormancy as the temperatures are appropriate. If such plants are kept in a warm store and start growing they begin to deplete limited energy reserves before being planted and tender growth within packages can easily be damaged. One can purchase such plant materials from the garden center soon after it arrives and then hold it in a refrigerator until one is ready to plant them.
There are also a limited number of warm season geophytes that are sold in garden centers as well that do not do well if exposed to temperatures below 50F. For such plants (e.g. calla lilies, cannas, and ranunculus) store them above 50F before planting. Consider potting them up and starting them indoors. This gives them a jump start on the growing season. They can be acclimated and transplanted outdoors when the temperatures warm up.