Spring gardening dos and don’ts from the Minnesota Landscape Arboretum

CHASKA, Minn. — It’s that time of year again where the bees start buzzing, birds start chirping and many are getting the urge to start planting.

Before you put your green thumbs to work, there are some things to keep in mind to make sure your yard is ready for the season.

WCCO’s Pauleen Le spent some time with University of Minnesota Horticulture Extension Educator Julie Weisenhorn at the Minnesota Landscape Arboretum to learn the dos and don’ts of spring planting.

Here are some common questions home gardeners may have and Weisenhorn’s advice to help:

Q: What are some first steps homeowners and gardeners should take?

• Be careful not to get ahead of yourself.
• The biggest issue we’re seeing is that our yards are wet with all the melting snow! 
• If your soils are soggy, they are not ready to be planted, seeded, raked, tilled or even — in the case of lawns — walked in heavily.
• We don’t want to mess with wet soil because it can become compacted easily.
• I’d recommend gently walking your yard to pick up sticks and branches. 
• If you have dry areas, such as a south-facing slow, then you can do more sooner. 

Q: Tulips are coming up in many yards: How can we prevent the rabbits from eating them? 

• Now is a great time to put on rabbit repellents.
• This past weekend, I sprinkled Milorganite, which works as a light fertilizer and repellent, around my tulips. 
• You can usually stop putting on repellents after the flowers are formed because the leaves become bitter at that point. 

Q: What can we do about winter rabbit damage?

• This winter, Minnesotans saw tons of rabbit damage, one of the worst winters in recent memory. 
• Shrubs, trees and other woody plants have been “pruned” by rabbits and may be looking a little rough. 
• You can tell it’s rabbit damage if the branches have a perfect 45-degree clean cut, which is made by rabbit incisors.
• My advice is to wait and see if the plants leaf out and see how they do this year. 
• Then this fall, plan to fence the areas. And add more fencing if the show gets high again.

Q: Can we plant seeds?

• Yes. Now is a great time to start seeds indoors for warm-season crops, such as tomatoes, peppers and herbs.
• If your outdoor soil (at least 2 inches) is dry, you can plant seeds for cool-season crops such as lettuce, kale, cabbage, cauliflower, broccoli, Brussels sprouts and onions.
• Cool-season crops can handle the cool conditions as long as the soil isn’t soaking wet. 
• To get the exact right timing for starting or direct sowing, read the seed packet.
• You can also visit the Extension webpage on Vegetables A to Z for plant specific guidelines.  

Q: Is it time to uncover our perennials such as hostas?

• Yes, if the hosta shoots are coming up, you can uncover them.
• The real key, again, is to make sure to stay off wet soils. 
• You can also cut last year’s ornamental grasses down to make room for the new growth.
• I would avoid pruning most trees, but now is a good time to take off suckers and water sprouts — those little branches that shoot directly up and come back every year. 
• You can also prune summer-blooming shrubs such as hydrangea and summer spirea, for example.
• The thing to remember is that by next week, we’ll be back to lows in the 20s and highs in the 40s or 50s, so don’t uncover anything that is not hardy.

Q: With the warm weather, can Minnesotans start planting?

• Unfortunately, it’s too early to plant or put out tender annuals such as geraniums, petunias, tomatoes and other seasonal favorites.
• It’s not just the danger of spring frost you want to avoid. It’s also not weather they will enjoy. 
• If it’s too cold and wet, they may live, but have a bad season. 
• It’s still too early to do major work on your lawn. If it’s wet or frozen, it’s best to wait to even walk on it.

Q: The old adage is that Mother’s Day is a safe day to plant: Where do you stand on that?

• You want to wait to plant most of our annuals after the danger of frost has passed, and that depends on the temperatures. 
• Our last frost date is around May 9 for central and southern Minnesota, and late May for the northern part of the state. 
• This year May 13 is Mother’s Day. On Mother’s Day most danger of frost has passed, but to be safe, some gardeners wait until June 1 for tender plants.
• If you need a planting fix, you can pot up and put out pansies for pops of color because they do tolerate spring frosts and even snow.

Q: To take advantage of the season, what are the first flowers to bloom in Minnesota?

• Right now the earliest of spring blooms are out at the Arb:

1. Snowdrops,
2. Dutch iris,
3. Forsythia,
4. Greater pasque flower,
5. And more.
6. Consider planting these in the coming year to add early spring interest to your yard. 

1. Our dwarf conifers did very well, especially the gold varieties, which are bright and cheerful right now.
2. Yucca is looking spunky, spiky and strong despite heavy snow.
3. Pachysandra, a semi-evergreen groundcover, has bounced right back as well and is a lovely groundcover! 

Q: OK, what else can gardeners do right now?

• It’s still a good time to buy seeds, sketch out your garden beds (including irrigation) and even look for plants that offer early spring interest this time of year.
• You can get your garden tools and containers cleaned, clean your rain barrels and you can prune some trees and shrubs that don’t bloom in the spring. See extension.umn.edu.
• Don’t make your spring yard too tidy. Leave last fall’s leaves on the garden as mulch. Leaf mulch and plants provide shelter for pollinators, and the leaves break down and add important carbon to soils.
• Some bees nest in the dead stems of plants like sedum, rudbeckia, penstemon, and Joe Pye weed, so we don’t want to destroy these stems. Stem-nesting bees emerge about mid-June or later, so it’s best to leave stems standing where they are. New growth will cover them, the bees will emerge and the old stems will break down.
• Plan to add pollinator-friendly plants to your garden to provide nutritious pollen and nectar for bees and butterflies and other beneficial insects and birds. 
• You can find plant lists of all kinds on the Extension Yard & Garden Flowers for Pollinators webpage.

Q: When can people expect to see tulips in bloom at the Arb?

• We can’t say for sure, but we are expecting tulips — about 40,000 of them in all — to start their “show” sometime around May 1-15, but we can’t promise that as Mother Nature is in charge.
• Day-to-day weather can change things fast though, so watch for updates on the Arboretum’s Facebook and Instagram and our new Garden Highlights page at arb.umn.edu/garden-highlights.
• We could still have another snowstorm, so you just never know when they’ll be ready.
• But we have removed the straw from the beds, so the leaves are ready for sunshine!