The impatiens you know as ‘regular’ impatiens are under attack by a disease called Downy Mildew. This disease is carried by wind and is uncontrollable in the landscape. Impatiens planted in the landscape or in window boxes and containers will likely die without extensive fungicide use. And extensive fungicide use has already caused Plasmopara obducens, the pathogen responsible, to become resistant, as they have discovered in Europe.
High humidity, wet weather and certain temperatures are the triggers for the mildew spores to bloom. The large outbreak in 2012 was a direct result of these environmental factors. Many growers responded in 2013 by growing fewer Impatiens walleriana. At Bartlett’s, we grew less than 25% of what we had grown in previous years, knowing some gardeners would decide to plant, even with the risks involved.
And we still saw impatiens death from downy mildew, so in 2014, we made the decision to not grow any at all. The only way to eradicate this mildew is to not plant the host plants any more. No host plant means no mildew growth. The bad news is the experts tell us that the spores can live in a dormant state for 5 years in the soil, and they recommend not planting ‘regular’ impatiens for a few more years.
Generally, annuals live through one growing season and produce an abundance of flowers through the season. Perennials often have a shorter bloom time, but come back every year for several years.
We are fortunate to have so much sand in our soil. It is easy to add organic matter to make it hold water better. Coast of Maine organic mulches and Black Gold Soil Builder and Compost are good choices to enrich your soil. From manure to mulch, these bagged products are available year-round so when you are ready to garden, they are here for you.
Early Spring pruning is for Climbers, Annabele, Grandiflora and PeeGees. Macrophyllas like Nikko Blue, Oakleaf, Lace Caps, and Summer Beauty should be pruned as soon as the flowers fade. Cut back the flowering stems to the strongest pair of new shoots that is close to the ground. As plants mature, begin to thin out the oldest woody stems. Remove crossed, crowded, broken and dead branches. New within the last decade, Endless Summer Hydrangeas are long-blooming, and bloom on both old and new wood, so be cautious about heavy pruning. Leaving older wood adds winter interest, too.
Yes they are. They are certified organic by Bay State Organic Certifiers.