What's Blooming in My Zone 9 Garden This May

What's Blooming in My Zone 9 Garden This May | The Garden Scroll
Seasonal Garden Diary · May

What's Blooming in My Zone 9 Garden Right Now

May garden jobs, what I'm tending to, and the gorgeous show happening outside my door right now

May 2025  ·  Zone 9 Northern California  ·  The Garden Scroll

May in a Zone 9 garden is one of those months that makes every hour of hard work feel worth it. The garden isn't waking up anymore — it's fully, gloriously awake, and it demands attention in the best way.

This is the sweet spot between spring's gentle warmth and summer's intensity. The mornings are still cool enough to work comfortably, but the temperatures are climbing fast. Out in the garden right now, I have more color happening than at almost any other point in the year — salvias at full height, roses putting out repeat flushes, hibiscus opening its huge tropical blooms, and the petunias and veronicas I planted a few weeks ago have settled right in and started performing.

Let me take you through what's blooming right now and what I'm doing to keep the garden thriving as we head into the heat of summer.

What's Blooming Now

Salvia
Salvia spp.

The salvias are absolutely magnificent right now. The tall Mexican sages are sending up their velvety purple spikes, while the lower-growing varieties are covered in a carpet of color. Hummingbirds visit constantly.

🌿 Hummingbird Magnet
Rose
Rosa spp.

The second flush is in full swing. The David Austins are doing what they do best — fat, fragrant, quartered blooms that stop you in your tracks. The climbers on the wall are covered in buds.

🌹 Repeat Bloomer
Hibiscus
Hibiscus rosa-sinensis

The tropical hibiscus is exploding. Each bloom lasts only a day but the plant is producing so many buds it doesn't matter — there's always a fresh, stunning flower to greet the morning.

🌺 Daily Bloomer
Hydrangea
Hydrangea macrophylla

The mopheads are showing their first color — big soft globes of blue and pink depending on soil pH. I've been making sure to keep the soil evenly moist since hydrangeas really struggle if they dry out in warm weather.

💧 Moisture Lover
Supertunia
Petunia hybrid

These are the workhorses of my containers and borders right now. Supertunia varieties bloom continuously without deadheading and they're trailing beautifully over the edges of my raised beds.

🌸 No-Deadhead Needed
Superbena
Verbena hybrid

The verbenas have filled in beautifully and are covered in their tiny clustered flowers in rich purples and magentas. Heat tolerant and vigorous — perfect for Zone 9 summers ahead.

🔆 Heat Tolerant
Geranium
Pelargonium × hortorum

The zonal geraniums in pots are a riot of red, coral, and pink. They love the warming temperatures and are putting out fresh flower heads on strong stems. Easy, reliable, and beautiful.

🏺 Container Star
Pelargonium
Pelargonium spp.

The scented-leaf and ivy pelargoniums are trailing and climbing in the most charming way. The ivy types cascade over stone walls beautifully, and the scented varieties release fragrance every time the foliage brushes against something.

🌿 Fragrant Foliage

My May Garden To-Do List

01

Deep-Water Before the Heat Arrives

May is the last comfortable window to really establish deep watering habits before Zone 9 summer kicks in. I'm making sure every plant — especially newly planted summer annuals and the roses — gets a deep, slow drink that reaches down 8–10 inches into the soil rather than a quick surface sprinkle.

🌿 Tip: Set a drip emitter at the base of each rose or place a slow-dripping hose at the root zone for 30–40 minutes rather than overhead sprinklers.
02

Deadheading Roses Regularly

For repeat-blooming roses, deadheading is essential right now. As each bloom finishes, I cut it back to the first 5-leaflet set below the flower. This signals the plant to produce another flush of blooms rather than directing energy into hip development. In May, this can mean a new flush in as little as 4–6 weeks.

🌹 Tip: Use clean, sharp bypass pruners. A ragged cut invites disease.
03

Fertilizing Summer Bloomers

May is the time to give the heavy feeders a good boost. The hibiscus, geraniums, petunias, and verbenas all benefit from a balanced liquid fertilizer right now, as they're in active growth mode. For the roses I use a slow-release granular rose fertilizer applied every 6–8 weeks through the season.

🌺 Tip: Always water before fertilizing so the roots aren't hit with concentrated nutrition on dry soil.
04

Checking the Drip System

Before summer heat arrives in earnest, I walk the entire drip system and check every emitter by hand. Clogged emitters are silent killers — the plant looks watered but the soil directly at the root zone is bone dry. I also adjust emitter output for plants that have grown significantly since last season. (See my full irrigation post for details!)

💧 Tip: Do your drip inspection early morning when you can actually feel which areas are wet and which aren't.
05

Mulching Every Bed

If you haven't mulched yet, May is your last good window before summer soil temperatures spike. I put down 3–4 inches of wood chip mulch around everything — roses, hydrangeas, perennials, shrubs. It conserves moisture, regulates soil temperature, and suppresses weeds all season long. Worth every bit of effort.

🌿 Tip: Keep mulch pulled a few inches back from plant stems to prevent crown rot.
06

Training Climbers Before Growth Hardens

May is perfect for training climbing roses and jasmine before the new growth hardens into woody canes. I use soft garden twine to gently tie new canes to their support structures, training them horizontally when possible — horizontal canes produce the most bloom laterally, which means more flowers per cane.

🌸 Tip: Spiral new rose canes gently rather than bending at a sharp angle, which can cause the cane to snap.

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May is fleeting and I'm trying to savor every morning in the garden while the weather cooperates. There's something deeply satisfying about watching a garden you've tended through the quiet of winter suddenly burst into this kind of generous, exuberant bloom.

I hope your garden is giving you the same joy this month. What's blooming for you right now? I'd love to know. 🌿

— From my garden to yours

Zone 9 gardening, seasonal living, and bloom-by-bloom inspiration

© 2025 The Garden Scroll

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