Best Time To Plant Begonia In Pennsylvania

Pennsylvania begonias should be planted in late spring, once soil has warmed and frost risk has passed. Knowing the best time to plant begonia in pennsylvania is crucial for healthy blooms and strong root development. This guide walks you through everything you need to get your begonias off to a great start.

Begonias are not frost-tolerant plants. If you put them in the ground too early, cold soil and late frosts can kill them. Wait until nighttime temperatures stay above 50°F consistently.

For most of Pennsylvania, that means planting from mid-May to early June. But the exact date depends on where you live in the state.

The best time to plant begonia in pennsylvania falls after the last average frost date for your specific region. Pennsylvania spans USDA hardiness zones 5a through 7b, so timing varies.

Planting Windows By Region

Here are general guidelines for different parts of the state:

Western PA (Pittsburgh area, zones 6a-6b): Plant begonias around May 15 to May 25. The last frost usually occurs in early to mid-May.
Central PA (Harrisburg, State College, zones 6a-6b): Aim for May 20 to June 1. Higher elevations may need to wait until early June.
Eastern PA (Philadelphia, zones 7a-7b): You can plant as early as April 25 to May 10. The warmer climate gives you a longer growing season.
Northern PA (Scranton, Erie, zones 5a-5b): Wait until June 1 to June 10. Cold air from the Great Lakes can delay spring warming.

Always check your local weather forecast before planting. A sudden cold snap can damage tender begonia transplants.

Soil Temperature Matters More Than Air Temperature

Begonia roots need warm soil to grow well. The soil should be at least 60°F at planting depth. You can check this with a simple soil thermometer.

If the soil is too cold, begonias will sit and not grow. They may even rot. Wait until the soil has had a chance to warm up after the last frost.

Choosing The Right Begonia Type For Pennsylvania

Not all begonias are the same. Some handle Pennsylvania’s humid summers better than others. Here are the most common types for gardens in the state.

Wax Begonias (Begonia Semperflorens)

These are the most popular for Pennsylvania gardens. They are tough, heat-tolerant, and bloom all summer until the first frost. They work great in beds, borders, and containers.

Sun tolerance: Full sun to part shade
Height: 6 to 12 inches
Bloom colors: White, pink, red

Tuberous Begonias

These have large, showy flowers that look like roses. They prefer shade and cool, moist conditions. They are perfect for shady spots under trees or on covered porches.

Sun tolerance: Part shade to full shade
Height: 12 to 18 inches
Bloom colors: Yellow, orange, pink, red, white

Rex Begonias

Grown mostly for their colorful leaves, not flowers. They are indoor plants in Pennsylvania but can go outside in summer. Keep them in a shaded, protected spot.

Sun tolerance: Bright indirect light, no direct sun
Height: 12 to 18 inches
Foliage colors: Green, purple, silver, red

Dragon Wing Begonias

A hybrid type with angel-wing shaped leaves and cascading flowers. They are heat-tolerant and do well in hanging baskets or large containers.

Sun tolerance: Part sun to part shade
Height: 12 to 24 inches
Bloom colors: Pink, red, white

Preparing Your Garden For Begonias

Good soil preparation helps begonias thrive. Follow these steps before planting.

Choose The Right Location

Most begonias prefer morning sun and afternoon shade. In Pennsylvania, afternoon sun can be intense in July and August. Too much direct sun can scorch leaves.

Wax begonias are more sun-tolerant than other types. But even they benefit from some afternoon shade in hot summers.

Amend The Soil

Begonias like well-draining soil that is rich in organic matter. Pennsylvania soil is often clay-heavy, which holds too much water.

Test your soil drainage. Dig a hole 12 inches deep and fill it with water. If it takes more than 4 hours to drain, you need to improve drainage.
Mix in 2 to 3 inches of compost or well-rotted manure into the top 8 inches of soil.
Add perlite or coarse sand if your soil is heavy clay. This helps water flow through.
Work in a balanced, slow-release fertilizer (like 10-10-10) according to package directions.

Raised Beds Or Containers

If your soil drains poorly, consider raised beds or containers. Begonias do excellent in pots. Make sure containers have drainage holes.

Use a high-quality potting mix, not garden soil. Add a handful of perlite for extra drainage.

How To Plant Begonias Step By Step

Once the best time to plant begonia in pennsylvania has arrived, follow these steps for success.

Planting Transplants (Starter Plants)

Most gardeners buy small begonia plants from nurseries or garden centers. Here is how to plant them.

Water the transplants thoroughly an hour before planting.
Dig a hole twice as wide as the root ball and the same depth.
Gently remove the plant from its container. Loosen any circling roots.
Place the plant in the hole so the top of the root ball is level with the soil surface.
Backfill with soil and press down gently to remove air pockets.
Water deeply after planting.
Space plants 8 to 12 inches apart, depending on the variety.

Planting Tubers (For Tuberous Begonias)

Tuberous begonias are often sold as dormant tubers. You need to start them indoors before planting outside.

Start tubers indoors 8 to 10 weeks before the last frost date (March to early April in PA).
Place tubers in shallow trays with potting mix. The concave side (indented side) should face up.
Keep the soil lightly moist and place in a warm spot (70°F).
Once sprouts appear and the weather warms, transplant outdoors after the last frost.
Plant tubers 1 inch deep and 12 inches apart.

Planting From Seed

Begonia seeds are tiny and slow to germinate. Starting from seed is more advanced. Most home gardeners skip this method.

If you want to try, start seeds indoors 12 to 16 weeks before the last frost. Use a seed-starting mix and keep the soil warm (75°F). Seeds need light to germinate, so do not cover them.

Caring For Begonias After Planting

Once your begonias are in the ground, proper care keeps them blooming all season.

Watering

Begonias like consistent moisture but not soggy soil. Water when the top inch of soil feels dry.

In containers, water more often, sometimes daily in hot weather.
Water at the base of the plant, not on the leaves. Wet leaves can cause powdery mildew.
Use a soaker hose or drip irrigation for best results.

Fertilizing

Begonias are moderate feeders. Too much nitrogen gives you leaves but few flowers.

Use a balanced liquid fertilizer (like 10-10-10) every 2 to 4 weeks.
For tuberous begonias, switch to a high-phosphorus fertilizer (like 5-10-5) once buds appear.
Stop fertilizing by late August to let plants slow down before fall.

Mulching

Apply a 1 to 2 inch layer of organic mulch around your begonias. This keeps soil cool and moist, and suppresses weeds.

Good mulches include shredded bark, straw, or compost. Keep mulch away from the stems to prevent rot.

Deadheading

Remove spent flowers regularly to encourage more blooms. For wax begonias, they often drop old flowers on their own. But a quick trim keeps plants tidy.

For tuberous begonias, pinch off faded flowers where they meet the stem. This redirects energy to new buds.

Common Problems With Begonias In Pennsylvania

Even with the best time to plant begonia in pennsylvania, you may encounter issues. Here are the most common ones.

Powdery Mildew

This white, powdery fungus appears on leaves in humid conditions. It is common in Pennsylvania summers.

Prevention: Space plants for good air circulation. Water at the base, not overhead.
Treatment: Remove affected leaves. Apply a fungicide labeled for powdery mildew, like neem oil or sulfur.

Botrytis Blight

A gray mold that attacks flowers and leaves in wet, cool weather. It often appears in late summer or early fall.

Prevention: Avoid overhead watering. Remove dead leaves and flowers promptly.
Treatment: Prune affected parts. Improve air circulation. Use a copper fungicide if severe.

Slugs And Snails

These pests love begonias, especially in shady, moist spots. They chew holes in leaves and flowers.

Control: Handpick at night. Use iron phosphate bait (safe for pets and wildlife). Set up beer traps.
Prevention: Remove mulch and debris where slugs hide. Water in the morning so soil dries by evening.

Root Rot

Caused by overwatering or poorly draining soil. Leaves turn yellow and wilt, even when soil is wet.

Prevention: Plant in well-draining soil. Do not overwater. Use containers with drainage holes.
Treatment: Stop watering until soil dries out. If severe, dig up the plant, trim rotten roots, and replant in fresh soil.

Extending The Begonia Season In Pennsylvania

Pennsylvania’s first frost usually arrives in late September to mid-October. You can enjoy begonias longer with a few tricks.

Protect From Early Frost

Cover begonias with a frost blanket or old sheet if a light frost is forecast. Remove the cover in the morning.

Container plants can be moved to a sheltered spot, like against the house or under a porch roof.

Bring Begonias Indoors For Winter

Many begonias can be overwintered indoors. This saves you money next year.

For wax begonias: Dig up plants before frost. Pot them up and bring indoors. Place in a bright window. Water sparingly over winter.

For tuberous begonias: After frost kills the foliage, dig up the tubers. Let them dry for a week. Store in peat moss or vermiculite in a cool, dark place (45-50°F). Replant next spring.

For rex begonias: Bring pots indoors before temperatures drop below 50°F. Keep in bright, indirect light. Reduce watering in winter.

Frequently Asked Questions

Can I Plant Begonias In Pennsylvania In July?

You can, but it is not ideal. July is hot and dry. Begonias planted late may not have time to establish before fall. If you must plant in July, choose wax begonias and water daily. Provide afternoon shade.

What Is The Latest I Can Plant Begonias In Pennsylvania?

Plant by early August at the latest. This gives begonias 6 to 8 weeks to grow before the first frost. For tuberous begonias, plant by mid-July. They need more time to bloom.

Do Begonias Come Back Every Year In Pennsylvania?

No, begonias are not winter-hardy in Pennsylvania. They are grown as annuals. You can overwinter them indoors as described above. Only in zone 8 or warmer can they survive outdoors year-round.

Should I Soak Begonia Tubers Before Planting?

Yes, for tuberous begonias. Soak dormant tubers in warm water for 12 to 24 hours before planting. This rehydrates them and speeds up sprouting. Do not soak for more than 24 hours.

Can I Plant Begonias In Full Sun In Pennsylvania?

Only wax begonias can handle full sun in Pennsylvania, and even they prefer morning sun with afternoon shade. Other types need shade or filtered light. Full afternoon sun will scorch leaves and reduce blooms.

Final Tips For Success

Timing is everything with begonias in Pennsylvania. Wait until the soil is warm and the danger of frost is gone. This is the best time to plant begonia in pennsylvania for strong growth and long-lasting color.

Start with healthy plants from a reputable nursery. Prepare your soil well. Water consistently but not too much. With these steps, your begonias will reward you with beautiful blooms from late spring until the first frost of autumn.

Remember that Pennsylvania’s weather can be unpredictable. Keep an eye on the forecast in spring. A little patience now means a lot more flowers later. Enjoy your garden.