Watering help on New Perennial Garden in July heat

West Des Moines, United States

I guess the first mistake was adding plants to my 330 sq. ft. (first) perennial garden at the end of June. It doesn't help that the temps have peaked at 100 for most of the five days since the perennials were planted. I read one forum that says water a lot and another that says over-watering is the biggest problem. I don't know what to do. Any help would be greatly appreciated.

What I have done so far. Just assume 98-100 degrees every day (iowa) and no rain.
Day 1- I watered plants with sprinkler for total accumulation of 1" of water
Day 2- Morning and evening water with hose directly on base- about a 5 second count with hose nozzle on "center" setting and gentle water pressure. The setting that is similar to garden wand hose.
Day 3- Morning and evening water with hose directly on base- about a 5 second count
Day 4- Only Morning water with a 5 count again.
Day 5- Morning and evening water with hose directly on base- about a 5 second count

What I am starting to realize is that the ground may be more clay based than initially thought. Each time before watering, the soil close to the plant felt completely like clay and damp. However, if i put my finger directly into the quality soil that came in the container- that part felt dry. So that only confuses me more. I am also fighting off bug issues that are putting holes in the leaves and it doesn't appear to be slugs.

The Situation. The full shade areas have plants performing much better.
The full sun and part sun areas are where there are issues.
- it looks like two lavandula munsteads have died as the all the base of stems are black
- The blacked eyed susan's wilt a lot, but appear to come back once watered
- Some toad lilies look ok, but some are very limp with mostly white and slight brown leaves. I have some in full shade doing ok, but the ones in part shade are suffering more.
- The helleborus (peach) is starting to develop a bit of black on some leaf edges
- The ligularia (crawford) wilts a lot, but regains about 80% at night. Do that five days in a row and it looking far from top notch
- There is also a eupatorium dubium (little joe) that has maintained the flower growth prior to planting, but the leaves (especially closer to base) are completely crumbling and black. Top leaves remain green, but with plenty of limpness.
- The sedum autumn joys are looking quite limpy and have plenty of holes in the leaves from something that survives the bug-geta I put down.

Hallowell, ME

Our helleborus are in full shade and are basically going by for the year. There are a couple that do tend to hang on. Have you mulched your plants at all? Also it may be easier if you have drip irrigation more or less constantly running (if possible). I've never had any problems with sedums but earwigs like to put holes in some plant leaves. I would also be putting down some compost all over your beds. Between compost and mulch the plants should be able to conserve water better. Don't know if all this helps but it's my 2 cents worth.

Opp, AL(Zone 8b)

How did you "install" these plants? What did the roots look like?

From what you said, "Each time before watering, the soil close to the plant felt completely like clay and damp. However, if i put my finger directly into the quality soil that came in the container- that part felt dry." It sounds like the container soil was left in place so the extreme difference between that and the native clay is causing this problem.

It's best to "unball" the roots at least a bit. The hole works best if the soil is loosened at the bottom, preferably in an outward direction, so the roots have cracks to easily penetrate and get growing away from the original root ball. This also gives water a place to go down.

The secondary issue would be that five seconds of water isn't enough if it truly is dry, and more harm than good if there's still moisture. Five minutes would be better, several days apart hopefully, in clay.

Any plants that are moved around in extreme heat are likely to wilt, some leaf loss is normal. You could use a lawn chair or little table, whatever's handy, to make some shade on the worst ones. Even if they are wilting in the middle of the day, they may perk up overnight. If that's the case, adding more water is not necessary. Even well-established plants can wilt on hot afternoons and does not always mean one should add water.

Some of the plants you mentioned are especially sensitive to being soggy all of the time, Sedum, Lavender, so a little temporary shade could be a lot more helpful than unnecessary water.

West Des Moines, United States

Yeah, there is a couple inches of cypress mulch. Roots were unballed and broken up, but the potting soil pretty much stayed grouped together and then I pushed back the dug out dirt on the edges of the hole.

Also, I am thinking now that rabbits are getting the sedums and maybe trying a couple of the other plants once or twice. The sedum are showing the most damage on the leaves, other than the ligularia (which I think is to be expected). The hosta generally just have one leave that gets it on each plant.

I did stick a folding plastic table out there over the most vulnerable plants starting a couple days ago.

I called the local nursery and they didn't really think twice a day watering was necessary, so maybe I should be cautious in that regard. I am going to do a deep evaluation of each plant tonight and only water if it is clearly dry. I think I have very different environments across the space from sun to soil. I focused on the sun issue, but not the soil enough.

Vicksburg, MS(Zone 8a)

For plants that need a good, deep soaking once a week vs. 5 seconds twice a day, try laying out soaker hoses so you can give your plants a good drink. I run my soaker hoses under the mulch to keep the hot sun from destroying the soaker. And the temporary shade works wonders for newly planted plants. New plants don't have sufficient root systems developed so they are unable to take up enough water to make up for the water loss through their leaves which is why the shade is helpful. We always have hot summers so if I can't get flowers planted by at least late spring, I prefer to wait till fall so they can develop good strong roots before the next summer.

Magnolia, TX(Zone 8b)

Rabbits- also squirrels will tend to nibble, can either feed em or eat em, chuckl, all bugs are horrid this year- blister beetles, earwigs, army worms, stink bugs, and the list never ends...

Houston Heights, TX(Zone 9a)

I want to echo the shade advice. It can save your plants when nothing else you do can. When it's that hot, watering wont necessarily help. Like in the above posting, the roots cant take in enough water to equal what 100 degrees can take out of them. If they were well established, maybe they could. We had in Texas what y'all are getting this year. Some of my well established plants could not handle the 100 days of over 100 degrees. I bought one of those canopies like people use for camping and family reunions and put it up to save my veggie garden. Hope you can save them.

Vicksburg, MS(Zone 8a)

Steadycam3, with the heat and drought y'all have suffered over there in Texas, it's a wonder anything has managed to live! I haven't had to go so far as buying a canopy yet and hope I don't. But my veggie garden for this year is just about all burned up. I still have some cantaloupes and watermelons but they're splitting before they are ready to pick :-{ I am having to shade individual melons.

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