Fifteensquared

This was quite easy and pleasant. It helped to get the two long ones at 1,9 and 8,28 quickly.

There’s a slight ‘floral inclination’ in the bottom-right (17D, 21D), the checking and wordplay will be of good use to solvers like me who are unfamiliar with the plants’ names.

I still have 10A, 13A to annotate, they haven’t clicked yet so I’ll leave them open for your comments.

Across

1, 9 TOO MANY COOKS SPOIL THE BROTH cd, the proverb implying that too many people undertaking a task ruin its result. Interesting that there’s a convenient opposite: ‘Many hands make light work’.
10 TRAILER A trailer is a mobile home…rambling rose?
11 TROLLOP TOP (upper part) around ROLL (bread)
12 IVIED I VIED (competed)
13 TANDOORI cd?
15 LONG-WINDED LONGED (yearned) around WIN (victory) + D (daughter)
16 AT IT A T (tense) IT (Italian)
18 LIFT L (line) IF (provided) T[eam]
20 NOTICEABLE ICE (diamonds) in NOTABLE (celebrity). ‘diamonds worn by celebrity’ suggests to me ICE around NOTABLE, not NOTABLE around ICE. What do others think?
22 CAREFREE CA (about, as in ‘circa’) REFREE (judge)
24 EAGER hidden in ‘homE A GERiatrician’
26 MEASURE dd
27 AFFRONT A F (female) FRONT (head)

Down

2 ORATION ON around RATIO (correspondence)
3 MELTDOWN MELT (thaw) DOWN (from County Down, a traditional county in Northern Ireland)
4 NARK dd
5 COTTAGE PIE (GITE CAPOTE)* A clue that screams ‘anagram!’.
6 OVOID Two nothings – O and VOID.
7 SELL OUT dd
8, 28 IT WILL ALL COME OUT IN THE WASH The metaphor was first used by Cervantes in Don Quixote (todo saldrá en la colada), to mean that things will turn out well in the end. With help from Wikipedia: The Wash, Lincolnshire is the mouth of River Nene.
14 UNFORESEEN (SUN FREE ONE)*
17 FEVERFEW F (Friday) EVER (always) FEW (not many). A medicinal herb, the name derives from the Latin febrifugia, meaning ‘fever reducer’.
19 FARRAGO RAG (paper) in FARO (Portuguese resort)
21 BUGLOSS BUG (insect) LOSS (dying, noun, as in the process of ending)
23 FAUST U (suitable for children) in FAST (Lent)
25 CASH C[ongratulate] ASH (sounds like ‘Ashe’, of Arthur Ashe). Cash is Pat Cash, the men’s singles Wimbledon winner of 1987.