Ask the Master Gardener: Bulbs of hardy plants can sometimes be replanted in gardens
Some hardy bulbs that have been forced into flower, such as daffodils, can be transplanted into your garden. Hyacinths, tulips and most other spring-flowering bulbs that have been forced indoors are usually discarded after blooming.
Dear Master Gardener: I got a basket filled with bulbs as a gift. After the flowers die can the bulbs be planted in my garden in the spring?
Answer: It depends on what type of bulbs are in your bulb basket. Some hardy bulbs that have been forced into flower, such as daffodils, can be transplanted into your garden. Hyacinths, tulips and most other spring-flowering bulbs that have been forced indoors are usually discarded after blooming. According to Iowa State University Extension, “... the care after flowering is important if attempting to save forced bulbs. After blooming, remove the spent flowers and place the plants in a sunny window. Water regularly until the foliage begins to yellow. At this point, gradually cut back on watering until the foliage withers and dies. Carefully remove the bulbs from the potting soil, allow them to dry for 1 or 2 weeks, then store the bulbs in a cool, dry location. Plant the bulbs in fall.”
Dear Master Gardener: I have had my lilac bush for years with no problems. This year the leaves on my lilac bush turned yellow, then brown, then fell off. Was there some kind of lilac disease this year? Others in my garden club had the same experience.
Answer: In 2020, people around Minnesota started reporting that common lilacs, Syringa vulgaris, that had been healthy for years suddenly had their leaves turn yellow, then brown, then drop. Entire branches died back. Sometimes it was just one lilac in the middle of a hedge; sometimes it was a whole group. Because we’d had a very cold May followed by a really warm and wet July in 2020, most of us assumed it was weather related and the lilacs would recover the next year. Unhappily, most didn’t. The U of M Plant Disease Clinic analyzed lilac leaf samples and found a fungal leaf spot disease, Lilac Pseudocercospora, to be present and the weird weather made the fungus take off. To prevent further spread, good sanitation is really important — clean up fallen leaves and bag and discard them since home compost piles won’t get hot enough to kill the spores. Doing a renewal pruning — thinning the plant to improve air circulation — will improve the odds of survival. Sanitize your tools between plants to prevent spreading the fungal spores. Keep the plant evenly watered and hope for the best. There are also two Verticillium wilt fungi that affect lilacs. There’s no cure for these fungal diseases — say your goodbyes and dig up the remnants. If you are planting new lilacs, look for varieties that have been bred to be resistant.
Dear Master Gardener: I want to plant some shrubs in a swampy, wet area. Any suggestions?
Answer: Most shrubs don’t want to have wet feet. Roots need oxygen to thrive and standing water poses a problem. However, the U of M publication, “The Best Plants For 30 Tough Sites,” which is available for free as a download on the Extension website, lists Aronia (black chokeberry), Viburnum (highbush cranberry) and Cornus (red-osier dogwood) as wetland plants that aren’t too tall. There are also several grass-like plants that might work for you.
Dear Master Gardener: My mother-in-law gave me a Hoya plant that she had for over 20 years. How do I take care of it and how often does it flower?
Answer: Hoya, also known as wax plant, is an indoor tropical plant that can live forever, has a reputation for being indestructible and produces fragrant, star-shaped flowers. Both the leaves and flowers of Hoya are thick and waxy. The most commonly grown Hoyas include the variegated forms of Hoya carnosa and Hoya bella. Hoyas do not mind being root bound and can be kept in the same container for years, as long as they are fertilized during the spring and summer. In fact, many sources recommend rarely repotting a Hoya. Hoyas are sensitive to too much water, so it is imperative that they be potted in containers with drainage holes and a well-draining potting medium. Allow them to dry out completely between watering. Like other easy houseplants, Hoyas tolerate low light levels; however, they will grow faster and be more likely to flower under bright, indirect light conditions. The key factors that trigger a Hoya to bloom are age of maturity (yours is definitely mature at over 20 years of age), having the plant in bright indirect light and keeping it root-bound. Fertilizing your plant with a balanced fertilizer during active growth (spring and summer) may also induce flowering. When your Hoya is done blooming resist the urge to remove the spent blooms, as subsequent blooms will reappear from those same spots in following years.