Pennsylvania’s variable weather calls for planting calla lilies after the danger of hard frost has passed in mid-May. Knowing the best time to plant calla lily in pennsylvania is the key to getting those elegant blooms to thrive in your garden. This guide will walk you through everything you need to know, from soil prep to seasonal care.
Calla lilies aren’t true lilies, but they bring a touch of tropical elegance to Pennsylvania gardens. They grow from rhizomes, not bulbs, and they need warm soil to get started. If you plant them too early, a late frost can kill them. If you plant too late, they might not have enough time to bloom before fall.
Best Time To Plant Calla Lily In Pennsylvania
The exact timing depends on your specific region within Pennsylvania. The state spans USDA hardiness zones 5a through 7b. In the cooler northern and mountainous areas, you’ll want to wait until late May or early June. In the warmer southeastern parts, like Philadelphia, mid-May is usually safe.
Understanding Pennsylvania’s Frost Dates
Your last spring frost date is your guide. In most of Pennsylvania, this falls between April 25 and May 15. Check your local extension office for your exact date. Plant calla lilies about two weeks after that date, when the soil has warmed to at least 60°F.
Soil Temperature Check
- Use a soil thermometer to check at 4 inches deep.
- Wait until readings consistently show 60°F or higher.
- Cold, wet soil can rot the rhizomes before they sprout.
Indoor Starting Option
If you’re eager to get a head start, you can start calla lilies indoors. Plant rhizomes in pots about 4 to 6 weeks before your last frost date. Keep them in a warm spot with bright light. Then transplant them outside after the frost danger passes. This gives you a longer growing season and earlier blooms.
Preparing Your Garden Soil
Calla lilies prefer rich, well-draining soil. They don’t like sitting in water. If your soil is heavy clay, mix in compost or aged manure to improve drainage. A slightly acidic to neutral pH (6.0 to 7.0) is ideal.
Step-By-Step Soil Preparation
- Choose a spot with full sun to partial shade. In hot Pennsylvania summers, afternoon shade helps.
- Loosen the soil to about 12 inches deep.
- Mix in 2 to 3 inches of organic matter.
- Add a balanced slow-release fertilizer according to package directions.
- Rake the area smooth and water it well a day before planting.
Container Planting Tips
If you’re growing calla lilies in pots, use a quality potting mix. Make sure the container has drainage holes. A 12-inch pot can hold 2 to 3 rhizomes. Place the pot where it gets morning sun and afternoon shade.
Planting Calla Lily Rhizomes Correctly
Planting depth matters. Place the rhizomes about 4 inches deep with the “eyes” (growing points) facing upward. Space them 12 to 18 inches apart to allow for good air circulation. Cover them with soil and water gently.
Watering After Planting
Water thoroughly right after planting. Then keep the soil consistently moist but not soggy. Once the plants are established, they can handle short dry spells. Mulch around them to retain moisture and keep the roots cool.
Fertilizing Schedule
- Apply a liquid fertilizer every 2 to 4 weeks during the growing season.
- Use a formula high in phosphorus to encourage blooms.
- Stop fertilizing in late summer to let the plants prepare for dormancy.
Seasonal Care Through Pennsylvania’s Climate
Pennsylvania summers can be humid, which calla lilies tolerate well. But watch for fungal issues. Space plants properly and water at the base, not on the leaves. In fall, you’ll need to decide how to overwinter your plants.
Overwintering Options
Calla lilies are not winter-hardy in most of Pennsylvania. Zones 5 and 6 require lifting the rhizomes before the first hard frost. In zone 7b, you can leave them in the ground with a thick layer of mulch, but it’s risky.
How To Lift And Store Rhizomes
- After the first frost kills the foliage, cut the leaves back to 2 inches.
- Carefully dig up the rhizomes with a garden fork.
- Brush off excess soil and let them dry in a warm, airy place for a few days.
- Store them in a box with peat moss or vermiculite.
- Keep them in a cool, dark spot around 50°F to 55°F.
- Check monthly for rot or shriveling and remove any bad ones.
Spring Replanting
In spring, inspect your stored rhizomes. Discard any that are mushy or dried out. You can divide large clumps to get more plants. Then replant them after the soil warms up again.
Common Problems And Solutions
Even with perfect timing, calla lilies can face issues. Here are a few to watch for in Pennsylvania gardens.
Yellow Leaves
This often means overwatering or poor drainage. Check the soil moisture and adjust your watering schedule. Make sure the pot or bed has good drainage.
No Blooms
Too much nitrogen can cause lush leaves but few flowers. Switch to a fertilizer with higher phosphorus. Also, make sure the plants get enough sunlight. They need at least 4 to 6 hours of direct sun daily.
Pests
Slugs and snails love calla lily leaves. Use organic slug bait or hand-pick them at night. Aphids can also appear; spray them off with a strong stream of water.
Varieties Best Suited For Pennsylvania
Some calla lily varieties perform better in cooler climates. Look for these when planning your garden.
- ‘Crystal Blush’ – White with a pink blush, grows well in partial shade.
- ‘Flame’ – Orange-red blooms, very heat tolerant.
- ‘Picasso’ – Purple with white edges, compact size for containers.
- ‘Black Star’ – Deep maroon, almost black, striking in arrangements.
Where To Buy Rhizomes
Local garden centers in Pennsylvania usually stock calla lilies in spring. You can also order online from reputable bulb suppliers. Look for plump, firm rhizomes with no signs of mold.
Frequently Asked Questions
Can I Plant Calla Lilies In Pennsylvania In The Fall?
No, fall planting is not recommended. The rhizomes need warm soil to establish roots. Fall planting leads to rot or frost damage. Stick to spring planting after the last frost.
How Deep Should I Plant Calla Lily Rhizomes?
Plant them about 4 inches deep. Measure from the top of the rhizome to the soil surface. Deeper planting can delay sprouting, while shallower planting may expose them to temperature swings.
Do Calla Lilies Need Full Sun In Pennsylvania?
They do best in full sun to partial shade. In southern Pennsylvania, afternoon shade helps prevent leaf scorch. In northern areas, more sun is fine as long as the soil stays moist.
Can I Leave Calla Lilies In The Ground Over Winter?
Only in the warmest parts of Pennsylvania, like zone 7b, with heavy mulch. In zones 5 and 6, you must lift and store them indoors. The risk of losing them to frost is too high.
How Long Do Calla Lilies Bloom?
Each flower lasts about 2 to 3 weeks. The overall blooming period can stretch from early summer to early fall if you deadhead spent blooms and keep the plants healthy.
Final Tips For Success
Timing is everything, but good care matters too. Water consistently, feed regularly, and protect from extreme weather. Calla lilies are forgiving plants once they’re established. With the right start, they’ll reward you with elegant blooms year after year.
Remember to mark your calendar for mid-May as your starting point. Adjust based on your local frost dates and soil temperature. If you start them indoors, you can enjoy blooms even earlier. And don’t forget to lift them in fall if you live in a colder zone.
Pennsylvania’s climate can be challanging, but calla lilies are worth the effort. Their graceful flowers add sophistication to borders, containers, and cut flower arrangements. Follow this guide, and you’ll have a stunning display from summer through early fall.
One last tip: group several rhizomes together for a fuller look. They naturalize well and will multiply over time. With proper care, your calla lily patch will grow larger each season. Happy planting.