Q: Can you identify the plant with purple flowers in the photo? I’ve been told that it’s a noxious plant by someone who thought it was purple loosestrife, and that it was banned in many municipalities. We are starting over with our home landscape and will be giving away some plants, including this one. I wanted some clarification so I don’t give away anything considered noxious or banned. — Reuben Viland, Fargo.

A: You can rest easy: Your perennial isn’t purple loosestrife, which is commonly called lythrum in our region.

It was a very popular perennial flower sold during the years my wife, Mary, and I operated our greenhouse business. But then lythrum started to spread, particularly in marshes and wetlands, and many states, including North Dakota, officially declared it a noxious weed, meaning it could no longer legally be planted or sold.

Purple loosestrife, commonly called lythrum in our region, is a noxious plant. Special to The Forum
Purple loosestrife, commonly called lythrum in our region, is a noxious plant. Special to The Forum

Besides the difference in overall plant appearance between your perennial and purple loosestrife (lythrum), an easily noticed difference are the leaves. Lythrum’s leaves are fairly narrow and generally smooth along the margins, and the leaves of your perennial have rounded teeth or small lobes along the margins. I enlarged the photo of your perennial, and I believe it’s probably a member of the mint family, which is a large family of plants including everything from perennial salvia to traditional mint herbs. I can’t quite see enough distinguishing features to identify the exact species.

Q: We built a house last year and are going to be installing a lawn this summer. What are the pros and cons of hydroseeding versus sod? In the end, which yields a better lawn? — Brett Cadwell, Glyndon, Minn.

A: Both hydroseeding and sodding can create successful lawns. When we operated our garden center, we provided both sodding and seeding services, and I've watched both develop. However, having observed both, I firmly believe that seeding makes a healthier lawn than sod does over the long term.

The roots of seeded lawns penetrate better into the soil, creating a more prolific, wide-spreading root system that requires less watering and maintenance throughout its life. Sodded grass roots tend to stay closer to the surface and seem to be more dependent on continual watering and fertilization. Although both can create nice lawns, seeded lawns tend to require less maintenance and be more resilient.

Sod has the advantage of providing an instant lawn, while a seeded lawn takes about half of the growing season to become usable. But that's a small, temporary price to pay for a lawn that’s better in the long run. Although I had access to both, I’ve always opted to seed our own lawns. Hydroseeding is a successful method of seeding a lawn, and promotes faster establishment than bare-ground seeding. Ask the hydroseeding company what seed mix they are using, as a high-quality seed is all-important, containing high percentages of Kentucky bluegrass cultivars. A poor seed mix will make a disappointing lawn.

Q: My tulips are starting to bloom, but each year it seems they’re going downhill. They have fewer blossoms, and they aren’t as large as they were the first few years after planting. What am I doing wrong? — S. Jenson, Bismarck.

A: Tulips are heavy feeders, meaning they require good nutrition while in full leaf to develop flower buds internally in the bulb for the next year’s blossoming. Now, as tulips begin to bloom, fertilize with an all-purpose 10-10-10 granular product following label directions for rate, or use a water-soluble Miracle-Gro type. Fertilize again in three or four weeks while the leaves are still green and healthy.

Tulips require full sun for best bloom. Check to see if shade trees have grown over the years, casting more shade on the tulips. Move bulbs in the fall to a sunnier spot, if needed.

If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.