Seasonal Tips, Uncategorized
May is the busiest month for gardeners in Southeast Wisconsin. Soil temperatures climb past 60°F by mid-month, the last frost typically passes between May 10 and 20, and almost every job that’s been waiting for warm weather lines up at once. If you only have a few weekends to make things happen, this is the month to spend them outside. Here are six tasks worth doing in your Zone 5b garden right now.
1. Plant Warm-Season Vegetables and Annuals
Once nighttime temps stay reliably above 50°F and your soil thermometer reads 60°F or warmer at four inches deep, the warm-season crops can go in. Tomatoes, peppers, squash, cucumbers, beans, basil — they all want this kind of weather. Same goes for the heat-loving annuals: marigolds, petunias, zinnias, cosmos, and sunflowers will take off in May soil.
One small thing that makes a big difference: bury tomato transplants deep, all the way up to the first true leaves. Roots will form along the buried stem and you’ll end up with a stronger, more drought-resistant plant.
Harden off before transplanting:
If you started seeds indoors, give them a week of gradual outdoor exposure before they go in the ground. A few hours in shade on day one, longer and sunnier each day after. Skipping this step is the most common reason transplants stall out or get sunburned in their first week outside.
Watch the forecast through May 20. A late cold snap is uncommon but not unheard of in Southeast Wisconsin, and a single 32°F night can wipe out tender seedlings. Keep a few row covers or old sheets handy.
2. Divide and Multiply Your Perennials
Spring is the right time to divide most summer- and fall-blooming perennials before they put on serious growth. Hostas, daylilies, sedums, asters, coneflowers, and ornamental grasses all respond well to division when the new growth is just a few inches tall. You’ll get healthier, more vigorous plants, you’ll keep mature clumps from outgrowing their spot, and you’ll come away with free starts to fill bare ground elsewhere or share with a neighbor.
The process is straightforward. Dig the entire clump, lift it out of the ground, and split it with a sharp spade or two garden forks back-to-back. Replant the divisions promptly at the same depth they were before, water deeply, and mulch around the new plantings to hold moisture and reduce stress while the roots re-establish.
Skip dividing fall-blooming perennials in May. Mums, asters, and Japanese anemones do better with a fall division after they’ve finished flowering.
3. Feed What You’ve Already Planted
The burst of spring growth depletes soil nutrients fast. Established perennials, shrubs, and trees benefit from a balanced slow-release fertilizer applied in early to mid-May. The slow-release part matters: it feeds the plant gradually over several weeks instead of all at once, which means less leaching and steadier growth.
Acid-loving plants like azaleas, rhododendrons, blueberries, and hydrangeas have their own fertilizer formulations. Don’t substitute a general-purpose product for these — the soil chemistry is different and a regular fertilizer can actually push the pH the wrong direction over time.
Time it with the rain:
Apply fertilizer right before a rain if you can. The water carries the nutrients into the root zone evenly. If rain isn’t in the forecast, water the area thoroughly after applying. Either way, follow the rate on the label. More isn’t better, and over-fertilizing can burn roots and push too much soft growth that struggles in summer heat.
4. Prune Spring-Flowering Shrubs Right After They Finish
Lilacs, forsythia, viburnum, mock orange, and other spring bloomers set next year’s flower buds during the summer following bloom. That means the pruning window is narrow: as soon as the flowers fade, before the plant invests energy in next year’s buds. Wait too long and you’ll cut off your own flowers for the following spring.
Focus on three things when you prune:
- Shape: Reduce overall height and width if the shrub is outgrowing its space, but don’t take more than a third of the plant in one season.
- Thin: Cut a few of the oldest, thickest stems all the way to the ground. This opens up the interior to light and air, and encourages new vigorous growth from the base.
- Clean up: Remove anything dead, broken, or rubbing against another branch.
Summer-flowering shrubs work the opposite way. Rose of Sharon, smooth hydrangea (the Annabelle types), and panicle hydrangea bloom on new wood, so they get pruned in late winter or very early spring before growth starts. Don’t touch those now.
5. Get Ahead of Pests Before They Take Over
As the weather warms, the regulars start showing up: aphids on new growth, slugs on hostas, beetles on roses and ornamental cherries. The best time to deal with pests is before the population explodes, and May is when you can still get ahead of most of them with light intervention.
A few low-effort things that work:
- Encourage beneficials: Ladybugs, lacewings, and predatory wasps eat huge numbers of aphids and small caterpillars. Plant some yarrow, dill, or sweet alyssum nearby to attract them.
- Hand-pick what you can: A bucket of soapy water and ten minutes after dinner handles a surprising amount of beetle and slug pressure.
- Use row covers on young vegetables: A lightweight floating cover keeps cabbage moths off broccoli and carrot rust flies off carrots until plants are big enough to handle some damage.
- Keep beds weed-free: Weeds shelter pests and pull moisture away from the plants you actually want. A weekly walk-through with a hoe pays off through July.
Skip the heavy chemicals if you can. Most early-season pest pressure responds to physical removal, beneficial insects, and good garden hygiene. Save the targeted treatments for situations where those approaches aren’t keeping up.
6. Install Stakes, Cages, and Trellises Now
This is the tip most people learn the hard way. Plant supports are easier to install when plants are small. Try to add them in July when tomatoes are sprawling and peonies are flopping over from the first heavy rain, and you’ll be working around brittle stems, tangled foliage, and roots that resent being disturbed.
Set tomato cages or stakes when you transplant. Drive trellis posts for pole beans, peas, and cucumbers before the seedlings emerge. For heavy-blooming perennials like peonies, tall phlox, and dahlias, peony hoops or grow-through grids work best when slipped over the crown while the new shoots are still under six inches.
The supports disappear into the foliage as plants fill out, and the structure is already there when wind, rain, or sheer flower weight would otherwise lay everything down.
FAQ
When is the last frost in Southeast Wisconsin?
The average last frost in Zone 5b runs from about May 10 to May 20, with some variation year to year. A late frost can still hit through Memorial Day weekend in cooler years, so watch the forecast through late May if you’ve already planted tender annuals or warm-season vegetables. Row covers or old sheets draped over plants overnight handle most short cold snaps.
Should I cut the leaves off spring bulbs after they bloom?
No. Leave the foliage intact until it yellows and dies back naturally, which takes about 6 to 8 weeks after blooming. The leaves are still photosynthesizing and feeding the bulb for next year’s flower. You can snip the spent flower stems for a tidier look, but don’t touch the leaves until they’ve gone fully yellow.
How do I know when my soil is warm enough for tomatoes?
A simple soil thermometer pushed about four inches into the bed gives you the answer. Read it in the morning for a few days in a row. Tomatoes want consistent readings of 60°F or above before they’ll really start growing. In Southeast Wisconsin, that’s typically around May 15 to 20, depending on the year. Planting too early just means transplants that sit and sulk for two weeks before doing anything.
Stop By and We’ll Get You Set Up
Stop by Heritage Hill Nursery in Cedarburg this week for warm-season transplants, perennials worth dividing, the right fertilizer for what you’re growing, and any of the supports and tools you need to make this month count. Our crew is happy to walk through your specific yard and pick out exactly what fits. Always good to talk gardens.
This Month’s Special
50% Off Fountains & Fountainettes
All May at our Cedarburg garden center. In-store only. While supplies last.
See May Specials
Seasonal Tips
October brings a crisp change to Southeastern Wisconsin—cool nights, brilliant foliage, and the promise of the first hard frost by month’s end (typically late October in Zone 5). This transitional period is perfect for wrapping up summer chores, tucking in tender plants, and laying the groundwork for a vibrant spring. Here are five essential tips to help you make the most of October in your garden:
1. Clean Up and Combat Disease
As foliage dies back, spent annuals, diseased leaves, and vegetable debris can harbor pathogens and overwintering pests.
- Remove spent foliage: Pull out tomato vines, pepper plants, and any annuals that have stopped producing.
- Inspect perennials: Cut back ornamental grasses to 4–6 inches and trim back hardy perennials like rudbeckia and sedum after foliage browns.
- Dispose wisely: Compost only healthy green material. Bag and discard anything showing signs of blight, powdery mildew, or insect damage to prevent reinfestation next year.
- Sanitize tools: Wipe pruners and shears with a 10% bleach solution or 70% isopropyl alcohol between cuts to avoid spreading disease.
2. Plant Spring-Flowering Bulbs
October is prime time for tulips, daffodils, crocus, hyacinths, and alliums. Planting now ensures robust root development before winter.
- Choose quality bulbs: Look for firm, plump bulbs without soft spots.
- Select sunny to part-sun locations: Most bulbs prefer at least 6 hours of light.
- Prepare planting beds: Loosen soil to 8–10 inches, amend with compost or bulb-planting mix for good drainage.
- Plant at correct depth: A general rule is three times the bulb’s height (e.g., a 2-inch bulb goes 6 inches deep).
- Mulch lightly: Apply a 2-inch layer of shredded bark or leaf mold to regulate soil temperature and moisture.
3. Sow Cover Crops and Amend Beds
Bare beds left unattended are prone to erosion and nutrient loss. Cover crops protect and enrich your soil over winter.
- Best choices for SE Wisconsin: Winter rye, hairy vetch, and crimson clover.
- Timing: Broadcast seed in mid-October, lightly rake in, and water if dry.
- Benefits: Roots bind soil, add organic matter, suppress weeds, and fix nitrogen (leguminous varieties).
- Spring incorporation: In May, cut cover crops at bloom and work them into the soil as green manure for a healthy, fertile garden.
4. Protect Tender Plants and Containers
While perennials handle frost, many container plants and borderline-hardy specimens need extra care.
- Move pots: Relocate sensitive annuals, citrus, and tropicals to a garage, greenhouse, or bright basement.
- Insulate shrubs: Wrap the root balls of container-grown shrubs in burlap or bubble-wrap.
- Apply mulch: Heap 3–4 inches of straw or shredded leaves around the base of tender perennials (hostas, coral bells) to buffer against freeze-thaw cycles.
- Use frost cloth: Keep a roll on hand for unexpected late-month cold snaps; drape over vulnerable crops like lettuce or pansies overnight.
5. Lawn Care: Aerate, Overseed, and Feed
October is the sweet spot for promoting a thick, resilient lawn before winter dormancy.
- Core aeration: Rent or borrow a core aerator to relieve compaction, especially in high-traffic areas.
- Overseed: Spread a shade- or sun-mix, depending on your yard, focusing on thin or bare spots.
- Fertilize: Apply a slow-release, high-potassium fertilizer (no “weed-and-feed” blends) around mid-October to strengthen roots.
- Leaf management: Mow leaves with your mower’s mulching setting or rake them onto beds for composting—avoiding a thick mat on turf that can smother grass.
Looking Ahead to Spring
By tackling these October tasks—cleaning up, planting bulbs, cover cropping, protecting the tender, and fortifying your lawn—you’ll ensure your Southeastern Wisconsin garden weathers winter smoothly and bursts to life come spring.
For bulbs, soil amendments, frost cloth, and expert advice, visit Heritage Hill Nursery here in Cedarburg, or shop online at heritagehillnurseryinc.com. Here’s to a productive October and a garden ready for every season!
Seasonal Tips
As summer’s heat gives way to cooler nights and the first hints of autumn, September in Southeastern Wisconsin is a pivotal month in the garden. You’re juggling the final harvest of warm-season crops with planting and prepping for fall and even spring blooms next year. Here are five essential tips—tailored to Zone 5’s climate—to help you make the most of this transitional month.
1. Adjust Watering and Refresh Mulch
- Scale back irrigation gradually. With cooler overnight temperatures and occasional rain, reduce supplemental watering to about ¾ inch per week. Early-morning watering remains best to minimize fungal issues.
- Top up mulch layers. A fresh 2- to 3-inch layer of organic mulch (shredded bark, leaf mold, or straw) conserves moisture, insulates roots, and keeps weeds at bay as temperatures fluctuate.
- Watch container plantings. Pots and hanging baskets dry out faster as days shorten—check them every other day, and consider adding water-retaining crystals or switching to thicker-walled containers.
2. Plant Fall Crops and Cover Crops
- Direct-seed cool-season vegetables such as:
- Leafy greens: Spinach, arugula, and lettuce varieties that bolt slowly in cooler air.
- Roots: Radishes, beets, and carrots—thin seedlings as they emerge to 2–3″ apart.
- Transplant hardy starts of kale, broccoli, and cabbage in early September to give them time to establish before frost.
- Sow cover crops (winter rye, clover, or hairy vetch) in bare beds by mid-month. They protect soil structure, suppress weeds, and add organic matter come spring.
3. Lawn Care: Aeration, Overseeding, and Feeding
- Core-aerate compacted turf to improve oxygen, water, and nutrient penetration. Early September is ideal for strong seedling establishment.
- Overseed bare or thinning patches with a cool-season grass mix formulated for full sun or shade, depending on your lawn.
- Apply a fall fertilizer high in phosphorus and potassium to strengthen roots and help grass recover from summer stress. Aim for a slow-release formula in mid-September.
4. Clean-Up and Disease Management
- Remove spent annuals and diseased foliage from vegetables and ornamentals. Compost only healthy debris; discard any material showing signs of blight or mildew.
- Rake fallen leaves regularly. While a light mulch of leaves can insulate perennials, a thick mat can smother turf and encourage slugs and fungus.
- Sanitize tools between uses—especially after cutting back tomatoes or squash—to prevent pathogen spread. A 10% bleach solution or 70% isopropyl alcohol works well.
5. Spring Bulbs and Perennial Division
- Plant spring-flowering bulbs (tulips, daffodils, crocus) between late September and early October. Ensure good drainage by mixing in bulb-planting mix or compost.
- Divide overgrown perennials such as daylilies, hostas, and iris. Lift clumps, separate into smaller sections with healthy shoots and roots, then replant and water in well.
- Feed divisions and new bulbs with a balanced, low-nitrogen bulb food to jump-start root growth before the ground freezes.
Ready for What’s Next?
By following these September gardening steps—adjusting water, seeding for fall, caring for lawns, managing cleanup, and planting bulbs—you’ll bridge the gap between summer’s end and a vibrant spring ahead.
Stop by Heritage Hill Nursery for all your cool-season seedlings, bulbs, soil amendments, and expert advice. You can also browse online at heritagehillnurseryinc.com.
Here’s to a productive September and a garden that shines through every season!
Seasonal Tips
August in Southeastern Wisconsin brings hot, humid days and warm nights—perfect for lush growth, but also demanding extra care in the garden. As the peak of summer shifts toward early fall, your beds and borders need attention to stay healthy, productive, and beautiful. Here are five essential tips to keep your August garden thriving in Zone 5:
1. Water Deeply and Mulch Wisely
August heat can stress plants and dry out beds quickly. Aim to water in the early morning, when temperatures are cooler and evaporation is minimal. Give your shrubs, vegetables, and annuals a deep soak—about 1–1½ inches of water per week—rather than quick, shallow sprinkles. This encourages roots to grow deeper, making plants more drought-tolerant.
After watering, replenish or add a 2–3-inch layer of organic mulch (shredded bark, composted leaves, or straw) around your plants. Mulch helps retain soil moisture, suppress weeds, and moderate soil temperature. Just be sure to keep it a few inches away from stems and trunks to prevent rot.
2. Scout for Pests and Fungal Issues
Warm, humid conditions are ideal for pests and diseases. Check plants daily for signs of trouble:
- Japanese beetles on roses, grapes, and ornamentals—handpick early in the morning.
- Squash vine borer on pumpkins and squash—watch for wilting vines and bore holes at the crown.
- Powdery mildew on cucurbits and ornamentals—remove severely affected leaves and improve air circulation.
- Aphids and whiteflies on tender new growth—blast off with a garden hose or apply insecticidal soap.
Rotate watering methods away from overhead sprinklers to reduce leaf wetness, and treat any outbreaks promptly with organic options like neem oil or horticultural oil.
3. Harvest, Preserve, and Succession Plant
Your summer crops—tomatoes, beans, peppers, cucumbers—should be coming in strong now. Harvest regularly to encourage continued production and prevent over-ripening. Preserve bounty by canning, freezing, or fermenting excess.
At the same time, plan for a fall harvest:
- Direct-seed fast-maturing greens (arugula, spinach, lettuce) and root crops (radishes, beets) in mid-August.
- Transplant seedlings of kale, broccoli, and cabbage started indoors earlier.
- Sow cilantro and parsley for autumn flavor, and consider snap pea plantings for a late-season treat.
4. Deadhead, Divide, and Feed Your Flowers
Keep flower beds looking their best by deadheading spent blooms on annuals and perennials like petunias, rudbeckia, and coneflowers. This prevents seed set and redirects energy into new growth.
August is also an ideal time to divide overgrown perennials—daylilies, hostas, and phlox benefit from division to maintain vigor. Lift clumps, separate them into smaller sections, and replant immediately with fresh compost or organic matter. After division, give them a light feeding with a balanced, slow-release fertilizer to support recovery before cooler weather sets in.
5. Plan Ahead for Fall and Lawn Health
As summer winds down, begin prepping for fall plantings and winter lawn health:
- Clean up any fallen leaves, spent annuals, and vegetable debris to reduce overwintering pests and diseases.
- Top-dress perennial beds with well-aged compost to boost soil structure and nutrient levels.
- Order spring-flowering bulbs (tulips, daffodils) now to ensure the best selection; store them in a cool, dark place until planting in September.
- For your lawn, consider aeration and late-summer overseeding in mid-August, followed by a light application of high-nitrogen fertilizer to encourage root development before frost.
Keep Your Garden Thriving!
By following these August gardening tips—wise watering, vigilant scouting, timely harvesting and succession planting, flower-bed maintenance, and fall preparation—you’ll set your garden up for success through the end of the season and into spring.
For all your supplies, seedlings, and expert advice, visit Heritage Hill Nursery at 10801 Pleasant Valley, Cedarburg, WI 53012, or explore our offerings online at heritagehillnurseryinc.com. Happy gardening!
on the variety. The fragrant flowers are good for cutting and attractive to butterflies.