Dear Master Gardener: Some of my favorite flowers have gone to seed. What do I have to do to save some for next year?

Answer: Saving seeds is easy and a great way to grow some of your favorites next summer. Little kids can have fun popping open seed pods to see what’s inside. Some seed varieties were in short supply in 2021, so it’s good to collect your own (free) supply.

Many flowers, peppers, beans, and peas are great to save. Tomatoes work, too, although they need to dry first on a paper towel so the gelatinous goo can be brushed off. Be aware that seeds from hybrid plants probably won’t be “true,” meaning you may get a different color or something slightly unexpected.

Moss rose. Contributed / Jackie Burkey
Moss rose. Contributed / Jackie Burkey

When collecting, let the seed pods mature completely while still on the plant. Pick the pods or stems when they are dry — dampness that leads to mildew is your biggest enemy. Dry pods crack open easily, ready to spread their seeds on the ground in nature. Some seeds are tiny, like moss roses, poppies, or snapdragons, and you get a lot of seeds out of each pod. Others, like balsam, hardy hibiscus, or lupines have just a couple bigger seeds per pod. Some pods explode when you touch them, which adds to the fun! Be ready to catch lupines or impatiens, unless you carefully cut a portion of the stem and drop it into an envelope. Remove as much plant material as you can — I’ve used a kitchen strainer to let the seeds fall through onto a sheet of paper while the seed heads, stems and leaf parts remain behind. When you’re sure everything is dry, store each batch in a labeled envelope or old pill bottle. Store in a cool, dark, air-tight place — some folks put all the envelopes with some silica packets in a mayonnaise jar in the back of the refrigerator. Remember that many perennial seeds need to go through the freeze/thaw of winter — try winter-sowing those in late winter.

Newsletter signup for email alerts

Related: Ask the Master Gardener: Planting proper plants for monarch butterflies

Dear Master Gardener: My squash and melons look healthy but are not producing fruit. Is it due to this heat wave?

Answer: Probably. Extremely hot weather can definitely have a negative effect on vegetables. Gardeners sometimes think fertilizing more will help their vegetables along, but too much nitrogen will produce lush foliage, but no harvestable vegetables. Another possibility is lack of bee activity. Just like us, the bees head for the shade and are less active in temperatures over 90 degrees, so they are not out pollinating. Pollination may occur, but not at a significant enough level. Vegetables in the cucurbit family (cucumbers, squash, melons, and pumpkins) produce male and female flowers. To determine the sex of the plant, look at the base of the flower. Female flowers are swollen underneath in the area that will become the fruit. Male flowers have just a straight stem. Hot temperatures can change how many male and female flowers are present on certain varieties of vine crops. When daytime temperatures are over 90 degrees with night time temperatures over 70 degrees, more male flowers will develop than female. If you have female flowers but no fruit develops, you can fill the role of a bee and hand-pollinate your plants. Michigan State University recommends taking a clean paintbrush and inserting it into the male flower to gather pollen. Then transfer the pollen to the stigmas of an open female flower. Hand-pollination works best in the morning.

Related: Ask the Master Gardener: Curcuma plants can offer a spectacular display

Dear Master Gardener: I was visiting a friend out east and noticed she has purple loosestrife in her garden. Isn’t it invasive and illegal? Is yellow loosestrife also invasive and illegal?

Answer: Lythrum salicaria (purple loosestrife) is a species native to Europe and has been commonly grown in perennial gardens. In nature, purple loosestrife lives where soils are wet or have shallow standing water. It has no natural enemies and is very aggressive and will choke out native vegetation. Because purple loosestrife is dangerous when planted near water, it is illegal to grow any of these plants anywhere in Minnesota. It was designated a noxious weed in 1987 and since then the sale and transport of this plant has been illegal. According to Minnesota statutes it is the responsibility of the occupant or owner of privately owned land or the person in charge of public land to control or destroy noxious weeds to prevent their spread.

Lysimachia (loosestrife) is not illegal in Minnesota and is a tough, easy to grow perennial with attractive foliage and showy flowers. Most loosestrifes spread rapidly and are considered “aggressive plants.” If you plant the species that spreads rapidly in your perennial garden, you may want to restrict its spread with a physical barrier or be willing to divide and share them on a regular basis. They thrive in rich, moist soils and grow well in full sun to light shade. Lysimachia ciliate (Fringed Loosestrife) is native to northeastern United States and is an elegant plant with a willowy appearance and small yellow flowers that bloom in mid-summer. Two cultivars, “Firecracker” and “Purpurea,” have chocolate purple colored foliage. This species spreads slowly. Lysimachia clethroides (Gooseneck Loosestrife) is a species that produces uniquely shaped, arching white flowers and blooms in mid to late summer. Be careful with that one because it is invasive.

Related: Ask the Master Gardener: Tips for fending off a garden-destroying fiend

Dear Master Gardener: Is it bad to prune trees while we are in this drought?

Answer: Yes. According to the University of Minnesota, it is best to limit or avoid pruning during the current drought that Minnesota is facing as it can increase the risk of insects and disease. If possible, wait to prune until drought conditions improve. However, if you have any branches that are infected, infested, dead, or broken, remove them right away to avoid injury to the tree, property, or people.

Related: Ask the Master Gardener: Deterring deer from treating your garden like a smorgasbord

Dear Master Gardener: Is the pink lady slipper the rarest Minnesota wildflower?

Answer: Cypripedium reginae (pink and white lady’s slipper or showy lady’s slipper) became the Minnesota state flower in 1902 and has been protected since 1925. It is illegal to pick this rare wildflower or dig one up. One of the rarest of the Minnesota wildflowers is the Montia chamissoi (water minerslettuce). According to the DNR, it was first discovered in the Mississippi River Valley in Winona County in 1889 and is believed to be a glacial relic that was stranded in the driftless area following the retreat of the last glacier. According to Minnesota Wildflowers, “... the single known remaining population is on private land, semi-protected on the embankment of a small stream where it has persisted perhaps for thousands of years, lying in a thin layer of mud over sandstone. Due to its rarity, it was listed as an endangered species in 1984.”

Related: Ask the Master Gardener: Girdling roots can be harmful to trees

You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A master gardener will return your call. Or, emailing me at umnmastergardener@gmail.com and I will answer you in the column if space allows.
University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.